Microsoft Windows and Office Activation can be tricky at times and you might get blocked by Microsoft if you try activating more then a few times with a single key to prevent software piracy.

This policy is now being implemented more strictly after Microsoft blundered and offered free Windows 8 keys to users. To prevent such situation one can opt to use handy free utility Advanced Tokens Manager for safe backup and restoration of Microsoft Windows and Office activation files locally for restore when a clean install is done.

While the Microsoft Windows 8 Upgrade Key is intended only for upgrades from earlier Windows versions to Windows 8, there could be valid genuine reasons when a user would like to do a clean installation of Windows 8. If a user tries to do a clean install activation using the upgrade key they are shown the error below and no activation occurs. Luckily, if a user owns valid license key for previous Windows version they can use a simple registry hack (I assume legally) which enables them to bypass this activation error message.

Invalid Product Key

"The following failure occurred while trying to use the product key:
Code:
0xC004F061

Description:
The Software Licensing Service determined that this specified product key can only be used for upgrading, not for clean installs."