I purchased a copy of Windows 7 Ultimate at an auction. I subsequently installed it on one of my computers and everything went well. Not knowing that I could only install it on one computer I then installed it on my other computer. Everything was running well for a few days and now I keep getting a message that Windows 7 cannot activate. I don't want to purchase another copy of Ultimate and want to return to the original OS - Windows 7 Home that was preloaded on my Dell computer when I bought it. I tried to do a system restore to the date that I installed the Ultimate but it didn't work. Ultimate is still running. Do I have to do a complete reinstall from my backup recovery disks and return to square one from when my computer was new or is there something I can do to stop getting the activation error code. If I have to return to square one and reload from my recovery disks, I will, but I am trying to get around having to go through all that work, as well as the many, many, updates I will have to wait through. I am also worried about having to reinstall all of my software, addresses, etc. Any help would be appreciated.