hey i was upgrading to vista business on my laptop - a dell inspiron 8600. it's a couple years old, but i had run the vista RC1 before, and it worked just fine until my hard drive died (thru no fault of vista - it was going to go anyway). I tried upgrading Windows XP Home to Vista Business and i ran into the same problem yo uhad with the constant restarts.

What i had to do was reformat and reinstall XP using my restore disks and then do a clean install of Vista Business. Basically I lost a bit of data, but because it was a new hard drive, there wasn't much on there, and i had everything backed up. So if you had some data on there, I'm sorry to say it's probably lost. But now i got vista working.

Good luck and let me know if it works for you.