If you own a previous version of Windows that is qualified for the upgrade version of Windows 7, such as Windows XP or Vista, you may want to install Windows 7 on a machine without one of those previous versions currently installed, in other words perform a clean install.
Prior to Windows Vista, this was very easy. All you had to do was start the install process and then during this process you would be prompted for your old copy of Windows to be inserted into the CD/DVD drive and then the installation would continue. It was simple enough and a system that worked.
With Vista, this all changed and you could no longer simply provide your old copy of Windows. You had to have a previous (upgrade compatible) version of Windows already installed. The same still unfortunately applies to Windows 7.
There is however, a way around this. It’s a bit more time consuming, but it gets the job done.
Step 1: Install Windows 7 normally with your upgrade disc (using the custom option), but do not enter your product key during setup. Make sure to deselect “automatically activate when I’m online” as well.
Step 2: After the first install is finished, run setup from your Windows 7 disc again, but this time choose “Upgrade” instead of custom (advanced) install.
Voila, you just upgraded from Windows 7 to… Windows 7?
Yes, that’s right, Windows 7 is an acceptable upgrade path to itself.