64 Bit Vista - 64 Bit 7 Update

Hey all. I'm currently dual-booting my main operating system, Ubuntu 10.04 64 Bit, and my backup OS, Windows Vista, which is 64-bit also. Now when I tried to upgrade on my Vista Partition, it said I didn't have vista and I had to do a clean install! I haven't done any system modding before, so I have no idea why it wouldn't recognize it. The Vista OS is factory installed too, so there's no illegality problems. I've installed 7 on 3 other computers and this never happened!

Any help/reasons would be greatly appreciated

 

Bump!