Second time, I kept getting "DISK BOOT ERROR, INSERT SYSTEM DISK AND PRESS ENTER". I could get around that by using the recovery console from the XP CD and using "fixmbr", but it did it every 2nd or 3rd boot, which was pretty worrying.
This time, it seems to be working so far. I haven't installed the AMD processor driver or the nVidia IDE driver, and I'm still installing Windows Updates, so I'll see if that makes any difference. I also had windows freeze on startup a few times before, which hasn't happened yet.
So, I'll install everything, then take a ghost image and hope for the best...