After spending over 12 hours trying to install the Vista Ultimate upgrade on Vista Home Premium only to have it fail in the last few moments of the install, searching various message boards, looking through FAQs, and chatting with numerous tech support lackeys I was able to find an answer. If you get the error: “Failed to upgrade one or more components. Windows will reboot and undo the upgrade.” Then the go to the Control Panel then if you have it set to Classic View then Click on Programs and Features, else Click on Programs and then Programs and Features. Once that opens click on “Turn Windows features on or off” and un-check the following: Microsoft .NET Framework 3.0 Remote Differential Compression Windows DEF Replication Service
That should do it… Oh, and every also told me to unplug all external devices except for the monitor, keyboard and mouse.