If you’re looking to upgrade your existing Windows 7 or Windows 8.1 PC, go to Get Windows 10 to learn more about upgrade options. If you’re on an Enterprise or Education edition, the tool won’t work for a clean installation. Please see the Volume Licensing Service Center for more information. Step 1: Boot From the Windows 7 DVD or USB Device. To begin the Windows 7 clean install process, you'll need to boot from the Windows 7 USB or DVD if you're using a Windows 7 DVD, or boot from a USB device if your Windows 7 installation files are located on a flash drive or other external USB drive.
Windows 7 Pro Clean Install
Clean Install Windows 7 Professional 64 Bit
Here are detailed instructions with pictures:
http://windows.microsoft.com/en-us/windows7/help/upgrading-from-windows-vista-to-windows-7-custom?T1=tab01
Or you can use this if you want:
32bit to 64bit Custom Clean Install Steps
You can use an upgrade disk, but you can't do an in place upgrade from a 32 bit system into a 64 bit system, the only way is to do a custom clean install. This means you'll have to reinstall all your programs, but you can save your files and settings to an external storage before doing so with Windows Easy Transfer. Here are the steps according to Microsoft:
1. Run Windows Upgrade Advisor (http://windows.microsoft.com/en-US/windows/downloads/upgrade-advisor ) to see if there are any known issues that might affect the installation and whether you should install the 32 or 64 bit version of Windows 7.
2. Back up your files and settings. To avoid losing anything you'll need to save copies of all the files, photos, and other information you want to keep on to an external hard drive. Windows Easy Transfer (http://windows.microsoft.com/windows-easy-transfer ) is a free tool you can use to copy your information (but not programs) from your PC and then put them back after you install Windows 7. If you don't have an external hard drive you won't be able to use Windows Easy Transfer, instead you can copy files you want to keep on a USB flash drive, or on CD/DVD.
3. Locate the original installation disks and any associated product/license keys for the programs currently on your computer because you'll need to manually reinstall all your programs after you install Windows 7. You might be able to download some programs from the Internet.
4. Inset the Windows 7 DVD into your PC, restart, and boot from the DVD. When asked 'Which type of installation do you want?' click 'Custom (advanced).'
5. After Windows 7 is installed you can use Windows Easy Transfer to restore your files & settings, and use your installation disks to install all your programs.
Have Questions About Installing Windows 7?
FAQ - Common Windows 7 Installation Questions & Answers
http://windows.microsoft.com/en-us/windows7/help/upgrading-from-windows-vista-to-windows-7-custom?T1=tab01
Or you can use this if you want:
32bit to 64bit Custom Clean Install Steps
You can use an upgrade disk, but you can't do an in place upgrade from a 32 bit system into a 64 bit system, the only way is to do a custom clean install. This means you'll have to reinstall all your programs, but you can save your files and settings to an external storage before doing so with Windows Easy Transfer. Here are the steps according to Microsoft:
1. Run Windows Upgrade Advisor (http://windows.microsoft.com/en-US/windows/downloads/upgrade-advisor ) to see if there are any known issues that might affect the installation and whether you should install the 32 or 64 bit version of Windows 7.
2. Back up your files and settings. To avoid losing anything you'll need to save copies of all the files, photos, and other information you want to keep on to an external hard drive. Windows Easy Transfer (http://windows.microsoft.com/windows-easy-transfer ) is a free tool you can use to copy your information (but not programs) from your PC and then put them back after you install Windows 7. If you don't have an external hard drive you won't be able to use Windows Easy Transfer, instead you can copy files you want to keep on a USB flash drive, or on CD/DVD.
3. Locate the original installation disks and any associated product/license keys for the programs currently on your computer because you'll need to manually reinstall all your programs after you install Windows 7. You might be able to download some programs from the Internet.
4. Inset the Windows 7 DVD into your PC, restart, and boot from the DVD. When asked 'Which type of installation do you want?' click 'Custom (advanced).'
5. After Windows 7 is installed you can use Windows Easy Transfer to restore your files & settings, and use your installation disks to install all your programs.
Have Questions About Installing Windows 7?
FAQ - Common Windows 7 Installation Questions & Answers