If you have gone in for the option to upgrade from Windows Vista to Windows 7, and if you find that the upgrade attempt has failed and you get an error message
This version of Windows could not be installed, Your previous version of Windows has been restored, and you can continue to use it
The PC on subsequent reboot/s keeps showing you the same message.
In such cases, you may want to try the following:
1. Select Windows Vista instead of the default Windows 7 setup when you see the boot entry menu.
2. Insert the Windows Vista Media into the drive and exit the Windows Vista Setup when its launched
3. Click Start > All Programs > Accessories > Right click the Command Prompt icon > Click Run as Administrator.
4. Type the following command at a command prompt and hit ENTER
Drive:\boot\Bootsect.exe /NT60 All
In this command, Drive is the drive where the Windows Vista installation media is located.
5. Restart your PC.