Other Versions of Scratch. If you have an older computer, or cannot install the Scratch 2.0 offline editor, you can try installing Scratch 1.4. If you are a network administrator: a Scratch 2.0 MSI has been created and maintained by a member of the community and hosted for public download here.

1. Install Windows 7 From Scratch

Technical Level : Basic
Summary
A Clean Reinstall is often better than getting a new computer since most PC's come larded with sponsors' bloatware and duplicate utilities that interfere with much better versions built into Windows 7. For this reason most tech enthusiasts Clean Reinstall using the Product Key on the COA sticker affixed to machine. This guide compiles everything that works best in tens of thousands of installs I've directly helped with in forums since Windows 7 beta, and continues my Seven Forums web tutorial with 2+ million views.
Details

Install Windows 7 From Scratch

To save pages of space I provide blue links to illustrated tutorials instead of illustrating them in-line. You can open these in a new tab using your middle mouse button (scroll wheel) or from the right-click context menu. Please notify me in Comments section if any link is faulty, then google the name to get an alternate link for that operation.

Find the right Windows 7 .iso

There is a stable source for the WIndows 7 installation media ISO to download your licensed version here.

I would use 64-bit for 4gb or more RAM, 32-bit (x86) for 3gb or less RAM.
You can slipstream the latest Updates into the installer ISO to save at least an hour's Updating after install using Update 7 installation media. However it may take an hour to do this so consider how much you want this. Due to problems with Updates which have recently grown more serious, MS has also just released a rollup you can install or slipstream into media here: Simplifying updates for Windows 7 and 8.1 Windows for IT Pros .

Burn ISO to DVD or to USB flash stick (minimum size of 4GB required) using Windows 7 USB-DVD Download Tool or alternatively to DVD using ImgBurn at 4x speed, to flash stick using Rufusselecting UEFI for GPT for UEFI BIOS, or Legacy MBR for Legacy BIOS.
For UEFI installs format flash stick with Option One of UEFI Bootable USB Flash Drive - Create in Windows making sure the settings shown in picture don't jump around after adding the ISO. You have a UEFI install if Disk Management shows an EFI System partition on the hard drive, the BIOS shows UEFI settings and it's Boot menu offers to boot the DVD or a UEFI-formatted flash stick as an EFI device.

If your files are not organized now is a good time to sort them into the User folders for yournamed User account using one of The many ways to copy, move, or delete multiple files. I find the easiest way to do this is to browse on the left-hand Explorer bar to C:Users[Your User Account] to expand User folders, then in right hand pane browse to all locations with unsorted files and drag them separately or in groups to the desired User folder on Explorer bar. Finally delete unwanted files from each User folder.

For all browsers other than IE which stores Favorites in the User folder of that name, exportyour bookmarks to Documents now. Most browsers will also let you set up a sync to store your browser settings, Favorites and history in a Google account, Firefox Sync, or similar:

If your email is stored on computer, Google how to back up specific mail and account settings to get solutions like How do I import and export email, contacts, and calendars with Windows Live Mail? - Microsoft Windows Help.
Backup Quickbooks 2010+ Company files from where you keep them, the default location User/Public/Documents, or google your version's file location, or run a QB backup to Documents before backing them up.
De-authorize I-Tunes. You can back up your Sticky Notes to keep the one currently on your desktop following Sticky Notes - Backup and Restore.

Then back up your files externally by dragging or copying your named User account or active User folders to another hard drive, external drive, flash stick or disk. ▶ Copying files to an external drive - YouTube

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An alternative is to upload files to the cloud using Microsoft OneDrive which offers 15gb free storage for each Outlook/Live ID. Install and use the OneDrive app to drag User folders into OneDrive folder, monitor uploading progress by clicking Cloud icon in System Tray on bottom right end of taskbar. Once files are all uploaded, rightclick the Cloud Icon again to choose Settings and Unlink so that any accidental file deletions are not deleted in the Cloud. Step 7 will pick up with reinstalling OneDrive to recover your files. Remember that any accidental deletions always end up in OneDrive's as well as your PC's Recycle Bin.
For unbootable Windows copy data to another HD or USB device using the Windows 7 disk to Copy & Paste in Windows Recovery Console, free Paragon rescue disk, or a Linux boot disk.

You can Run and print an audit of hardware and software including installed Product Keys using Belarc Advisor. This audit assures you won't lose any paid software keys like Office. Note that the Windows 7 Product Key found by Belarc or another key finder will be an SLP batch key used at factory, if it has not yet been activated from COA sticker Key used for a Clean Reinstall. This SLP batch key cannot be used for reinstall. Methods for backing up Factory SLP Activation if the COA Product Key is not readable are not supported here but can be found on the web.
For unbootable Windows, you can read the installed Product Key and any Office key you don't have backed up using ProduKey - Recover lost product key (CD-Key) of Windows/MS-Office/SQL Server

If you have a Recovery partition it may not run after clean reinstall. You may want to make your Recovery Disks so you have a path back to factory condition, following the steps given in your PC's setup literature or in the Manual located on the Support Downloads webpage for your model computer. As an alternative to Recovery Disks you can save a Windows 7 Backup Image or more flexible Macrium Reflect Freeimage of the entire HD.
You can wait until afterward to see if Recovery or (Diagnostics) Tools partitions will run from boot to decide if you want to delete those partitions and recover the space into C or elsewhere (using Step 3 here). This information may be provided for your brand PC in the Special Notes at the end of this tutorial.
Write down the Product Key from COA sticker located on back or side of PC tower, bottom or under battery of notebook. Make sure you get the characters correct as this is a main cause of activation failure. You can input or Skip the key during install then afterwards activate at Control Panel>System, which may require a quick robocall. But put the key in a safe place so you have it for the life of the PC, which may outlast the sticker's readability.
The COA sticker looks like this:

Gather your program installers. For those lacking disks, you may find them on the program's Support Downloads webpage. Favorite pre-installed apps may be found on the Downloads webpage for your model computer or manufacturer-provided Apps Disk. Others may be found by googling. Some pre-installed apps may not be available for clean reinstall - more about this for your brand PC in the Special Notes at end.
If needed, Office reinstallation media can be obtained via Manage, Download, Backup, & Restore Microsoft Office Productsand activated with the Product Key you originally bought with it or audited using Belarc Advisor or ProduKey. A good free compatible alternative to Office is LibreOffice Free Office Suite or OpenOffice. You can also Try Office 365 for free to trial the new subscription Office suite fully integrated into the cloud.
Many of the favorite apps needed and desired for reinstall are available in the terrific app Ninite - Install or Update Multiple Apps at Once. This makes a custom installer you can save which keeps all app installers updated within.
Just in case, save in advance your Wireless or Ethernet LAN (wired) driver in your backup so if it isn't provided during install you can install it to get online quickly to install all Important and Optional Windows Updates - which will also provide most drivers. Your network LAN driver can be found on the Support Downloads webpage for your model PC. The exact make/model will be listed in your Device Manager under Network Adapters.

Install the Windows 7 .iso

Unplug all other HD's and peripherals except ethernet cable to increase chances of it starting up connected after install. If not prompted for wireless key during install it's likely you'll need to install the wireless driver immediately after getting to the desktop, or if ethernet LAN is working wait for wireless driver to come in via Windows Update.

Follow How to Enter Your PC's BIOS, near the storage settings make sure SATA controller setting is AHCI, then under Boot tab set the hard drive first to boot (unless you don't have a BIOS boot menu key in which case you need to set your Installation media device first to boot), Save Settings and Exit. If in doubt about whether you have a UEFI BIOS, comb the settings for UEFI, EFI, CSM, Legacy BIOS, Secure Boot - if none of these are present then you don't have a UEFI BIOS. If you have UEFI, check the PC or mobo's Support downloads webpage for latest firmware to install if necessary now.

Reboot tapping BIOS boot menu key to trigger installation media, as a UEFI/EFI device if you have a UEFI BIOS. Choose Custom Install, then at the 'Where do you want to Install Windows?' screen access the Drive Options (Advanced) to delete all partitions to Unallocated Space, create New and Format as desired, or just click Next to let the Installer auto-create and format needed partitions and begin install.

Whether to use more than one partition depends largely if you want your data in the OS partition, or have it linked from another partition to make C partition backup image smaller - this way if Windows 7 becomes irreparable you can re-image the OS/Programs to C and the data will be current and waiting safely in its own partition.
Due to lack of SP2 Win7 has no USB3 drivers so use a USB2 port for flash install; it may be necessary to disable USB3 controller in BIOS setup for install. If you're prompted for drivers for any other reason during install it almost always means a bad installer, so make sure ISO download completed and create another one.
If you have an UEFI BIOS, or receive an error that Win7 cannot be installed to disk because of its formatting, and cannot overcome the error by deleting all partitions, then you may need to follow the special steps to Install Windows 7 with UEFI (Unified Extensible Firmware Interface) including if necessary to Create UEFI Bootable USB Flash Drive, or may Bypass UEFI to Install WIn7. Remember to boot installer as UEFI Device. We can help troubleshoot UEFI problems as we do here every day.
Other Steps here to Troubleshoot Windows 7 Installation Failures - Windows 7 Help Forums

Get online to run all Windows Updates

Immediately after install check bottom right System Tray network icon to connect to your network if necessary. If only a TV icon with a red slash appears then open and extract network LAN driver, right click on Setup to Run as Administrator, install LAN driver watching System tray icon to choose network if required. Why can't I connect to a network? - Windows Help
Immediately after getting online install your AV. I suggest using a lightweight free Antivirus like Microsoft Security Essentials or the more aggressive Panda Cloud which perform well with the Windows 7 Firewall. Bloated AV's cause problems with Win7; if you're infected while using MSE I suggest adding inexpensive Malwarebytes Real Time Protection which also work together well.

Next open Windows Update to Check for Updates, select all Important and Optional Updates (except Bing, unless you prefer it) to install. After requested reboots, go back again to Check for Updates until there are no more. These Updates deliver drivers, critical system, hardware and security patches. I would accept them all to be safest, keep Updates set to Automatic and regularly check for Optional to install because often needed Updates are queued there.

If Updates stall or balk check your Start menu's Shutdown button for a '!' signaling there are Updates queued there for install at Shutdown. Perform a Shutdown to install them and then keep an eye on the Shutdown button if further rounds of Updates stall to clear them there first before proceeding to again Check for Updates. Most Update jams can be resolved by several reboots - real problems are one in a million.

If Updates will not install at all or endlessly Check for Updates, go into Windows Update 'Change Settings' and set it to Never Check for Updates, download and install manually Windows Updates KB3020369, followed by a restart and then KB3172605, then restart again. Now Check for Updates and they should appear. Install all Important and Optional, with necessary Restarts. Once all Updates are installed you can Change Settings again to Install Updates Automatically.

Any drivers still missing in Device Manager after all Important and Optional Updates are installed can be found on the Support Downloads webpage for the model PC or device, along with other OEM software which you can wait to see if you need.

I would not replace any drivers given by the installer or Windows Update unless performance problems point to that specific driver. We can help you troubleshoot these issues. If you install a driver and it performs badly you can Roll Back on its Driver tab in Device Manager.
'Standard VGA' Display driver is a placeholder driver which only should be used when no other possible driver will install as it will not allow Sleep or Hibernate. So if Updates don't provide a better driver, import it from the PC model's Support Downloads webpage - if necessaryeven Vista, or XP driver installed in Compatibility Mode. If this fails check the device maker's Support Downloads webpage to let it scan for the needed download to install.
Unknown Devices are often card reader drivers posted on the model's Support Downloads webpage along with other drivers which may be revealed by a function still missing on the PC such as laptop function keys or keyboard lighting, or can be traced using Device Manager - Finding Unknown Devices - Windows 7 Help Forums

Co-processor, SM Bus controller, USB and Storage controllers are often elements of the chipset. If no chipset is posted on your model's Downloads page, use the Intel Drive Update Utility or AMD Auto-Detect to find your chipset, or ask in our Drivers forum.
You can also trace any missing driver using Hardware Identification. It's often faster to google the Driver Detail's Hardware ID than to look it up.
I would not re-import any of the OEM software until you run for awhile to know for sure you need it. There may be patches on the PC's Support Downloads webpage needed to improve performance so browse them to be aware what's available as you test performance to decide if they're needed. But keep in mind re-installing OEM bloatware besides that which is absolutely needed for good performance or a specific function you need defeats the purpose of a Clean Reinstall.

Reinstall your programs

Install programs slowly over time to gauge performance changes after each. You can roll back bad effects of a Program install or Update(s) by uninstalling it or using System Restore.
Install your preferred Reader and Flash Player declining the Optional offer. I no longer recommend installing Java unless you know you need it or are prompted to install it to run a program, as it is an infection path.

Don't let programs write themselves into msconfig>Startup as they slow startup, become freeloaders on your RAM/CPU, can spy on you and cause conflicts. No video, sound or other driver software needs to start with Windows 7 unless you know you need special settings on these.
As illustrated in Startup Programs - Change uncheck everything except AV, gadgets (aka 'Sidebar'), Sync program, printer which scans from printer top, and Flash player updater (needed for safety and performance) in msconfig>Startup.
Then after reboot do the same in msconfig>Services after checking the box to 'Hide All MS Services.'
Check back with both lists periodically to see if anything writes itself back in, turn it off in its Program Preferences.
If you have any questions about a listing, Google it to learn what it does or ask us.
However I would not install any Google programs which are relentless spyware. Only use the stable Google search box in your browser and don't stay signed into any Google web apps.
Avoid spyware tracking cookies placing annoying interest ads by periodically Opting Out of Network Advertising. This will greatly relieve the banner ads which track your shopping habits and web searches.
The most important thing you can do to avoid spyware creeping in is to watch your program installs like a hawk at every step, because freeware authors have found ingenious ways to sneak in spyware with tricky check box choices - even in the License Agreement. Always do a Custom install and only allow the features you know you want, check later to remove anything extra in Control Panel>Programs and by running a full Malwarebytes and AdwCleaner scan (Step 12) which roots them out as deep as they can go.
Keep an eye also on your Browser Add-Ons or Extensions to only allow the ones you know you want or are required to make a page display correctly, including Flash, Shockwave, WMP or Quicktime plug-in, a reader, Silverlight. Also under Add-Ons monitor Search services to remove any but Google in the stable browser search box, tick the box to disallow any others to replace it.Strange search service are often spyware.
If you're prone to infection add the inexpensive paid real-time protection for Malwarebytes to run alongside a lightweight recommended AV, otherwise use its excellent free scanner as needed.

Recover your user files

Before copying your files into the new install, now would be a good time to download, install (declining trial), update and run a scan on them with Malwarebytes to make sure no infection is being re-imported.
If you backed up to OneDrive, reinstall the OneDrive App, wait for files to download from OneDrive into the OneDrive folder completely, then copy them into User folders, or move the User folders of the new Install into the OneDrive folder to Sync, Backup and Store your Files to the Cloud with OneDrive.
To copy your files into the new install, open the storage folder, open each User folder (Documents, Pictures, etc.). Next from the Organize tab choose Select All, drag the group to the corresponding folder on Explorer bar at left. Wait until the bar stops unfolding and hypertext confirms the precise copy location before releasing the left click.

If this method makes you nervous, right click on the Select All file group to Copy, then open the corresponding target user folder, in an empty space right click to Paste.
Do not copy hidden AppData folders from User Accounts as these are a corruption path- another reason not to use file transfer apps which can also lose files.
If you're using a separate data partition copy your User folders to it, then you can either move the new install's active User folders location to there following User Folders - Change Default Location, or right click each to link it to the related Library - Include a Folder then set it as default for that Library - Set Save Folder - Windows 7 Help Forums. Keep the empty C User folder in each library so you can easily see if something lands there and simply drag it to the linked User folder. If you move the User folders use another Backup Imaging app like free Macrium Reflectas the built-in one will want to include the data drive which now holds System files.
A simple free method is here to Sync, Backup and Store your Files to the Cloud with Onedrive - Windows 7 Help Forums that shows how to move your User folders into OneDrive folder on C or data partition for instant backup to the cloud and simultaneous synching across all of your devices using this method.
The User Favorites folder will populate IE Bookmarks. Import another browser's Bookmarks from HTML file backed up previously. Copy Quickbooks and other Program data into it's default folder location.

Activate the OS

Activation at Control Panel>System may in rare cases require an automated robocall to MS the first time to record your hardware signature in their servers. It will always work as long as you install the correct version and input the key accurately which is a frequent stumbling block - taking a well-lighted phone pic of COA sticker key to enlarge may help, or use a magnifying glass.

You should be offered to stay on the line to speak with an agent if the automated system fails to Activate Windows 7 by Phone. Another method is to open a Command Prompt, type slui 4, press Enter and follow prompts. If it fails stay on the line to speak with an agent.

You can easily configure and share files between PC's on the same network using Homegroup - Create.
On my installs users are most impressed by the spectacular beauty of the collected national editions' 120 Windows 7 Backgrounds slideshow. You can download the folder from http://1drv.ms/1shAWUu. Type Personalize in Start search box, choose Windows 7 Aero Theme, from Slide Show link Browse to Pictures Location, Select folder, Select All as a 30 minute random slideshow, Save Changes.
With gadgets no longer being supported due to supposed risk of infection we've never seen, what works better now for millions who love them is to install v.12 or higher of 8GadgetPack which supports Windows 7. It works the same except you'll need to hide the Sidebar. The MSN weather gadget similar to Win7's popular weather gadget can be easily installed to open from the same gadget pack.
When finished, clean and order the HD perfectly using state-of-the-art free CCleaner 'Run Cleaner' button and Registry tab.
Type 'Defrag' into Start Search box to run a Windows defrag and set its schedule to your liking. Never defrag an SSD!
Periodically run the above as well as a full scan with free Malwarebytes and AdwCleaneron-demand scanners, declining the trial unless you're prone to infection - in which case purchasing MBAM Real Time protection at $29 for life almost always resolves this, when run in tandem with your AV. Always check that you are running the latest version of the scanner and it is fully updated.
Take advantage of the perfectedWindows 7Power Options. Most users only need the Balanced Plan, ideally to Sleep at 30, Hibernate at 45-90, with Hybrid Sleep enabled. Many users prefer Hibernate to Shut Down as it keeps in place your open work and starts up much faster while still powering down. Note that timing out to Sleep without a Hibernate safety net will wear your RAM indefinitely until you come back (vacation? ).
Sleep and hibernation: frequently asked questions
Hibernate Shortcut - Create
After reinstall I always scan the logs to resolve repeat errors, check System Resources, search for Problem solutions, Generate a System Health Report - as shown in these basic Troubleshooting Steps for Windows 7 to bookmark.

Finally, save a Windows 7 Backup image to external or another internal HD so you never have to reinstall again - just do a System Image Recovery to the HD or it's replacement from booted DVD/Repair CD and the stored image.
I would save at least one baseline image after reinstall to replace needing to do a reinstall in the future. However some users like to have a more current image to choose from in which case I'd save a separate one as often as you want. Win7 imaging will save past images as long as there is enough room on the storage drive for a new image.
Note that built-in Win7 backup imaging is limited to restoring the OS to the exact same partition structure, so if you want a more flexible app try favorite free Macrium Reflect. Once you load the image and target hard drive, use the links under each existing partition to delete those you're replacing, then just drag your desired partitions to the target drive, note the new link created just below each to use sliders to adjust its size, then click Next using the default settings.

Henceforth if required to contact your OEM Tech Support do not tell them you Clean Reinstalled but troubleshoot as if you have the factory install. Otherwise they may refuse to support Clean Reinstall, but cannot void Hardware warranty. If you must ship the unit back for repair under Hardware warranty save a Windows 7 backup image and then run Factory Recovery beforehand.
Special notes for HP owners:
On newer models HP System Recovery may offer a Minimized OS Recovery option. This retains only the OS, Recovery Manager, HP Support Asst, HP Wireless LAN, drivers and activation, and is as close to a clean reinstall as you can get without doing one yourself. I would uninstall HP Wireless to use Win7's superior wireless manager.
If you format and reinstall only to C leaving all other partitions intact, F11 Recovery key should still work later if you need it. The helpful hardware diagnostics also listed on the ESC or F9 boot menu may also run after reinstall, so if they will run now from boot, I would save the small HP Tools partition to see if they remain bootable after install.
Problems with volume control lighting and HP Quick Launch buttons have been dealt with here and here.
Specific HP software which might be worth reimporting is discussed in HP Bloatware, or useful system utilities?
Some HP Recovery disks can have their files extracted to access favorite program installers using Accessing HP Recovery Disc Files.
Special notes for Dell owners:
If your Recovery partition is triggered at boot from the F8 System Recovery Options then it will no longer run after clean reinstall, so make your Recovery disks first, delete Recovery partition during reinstall.
The bootable Dell Diagnostics often will run after Reinstall so are worth saving if they will boot. Try it now to test your hardware and see if these work, choosing on F12 menu Diagnostics and then Utility Partition which sometimes has a fuller suite. If they run save the Dell Utility partition during install, if not delete all partitions. These tests can also be run online at Dell PC Diagnostics Dell US
Useful tips for Dell re-installation plus access to their forums to resolve questions can be found at Dell Community . The Dell Reinstallation DVD has only activation and a Dell logo added and can be used as long as it is labeled to include SP1.
Special Note for Sony Vaio Owners:
Software which enables F-key functions and illumination must be reinstalled from the Sony Support Downloads webpage in the order as shown here: Function keys don't work after clean install - Windows 7 Forums
Special Note for Samsung Owners:
Software which enables F-key functions and illumination may be labeled Easy Display Manager.
Special Note to Acer Owners
There is an OEM Preload folder hidden in the C:/ drive that holds all the pre-loaded software, including the eRecovery software.
Special Note for Lenovo Owners
The only OEM software I've found to be valuable is Lenovo Energy Management's features to preserve battery by maintaining a 60% charge when plugged in, and fan reversal to clean out dust. Download from your model's Support Downloads webpage or Power Manager for Windows 7 (32-bit, 64-bit), Vista (32-bit, 64-bit) - Notebook

Office Word version here.