HI i have just switched hard drives with 2 comptuers a pentium4 and amd athlon 64 3100 and i tired the instrucions in this post How to repair Windows XP/2000 if you are unable to boot into Windows
and got the pentium working i have tried it on the athlon64 and it loaded all the things from the cd and did all the fancy stufff at the beginning untill it had to restart. it then restarted and would have no problems starting up untill the windows screen whould show up with the loading bar. the little curser would go accross 5-7 times then blue screen would flash and it would restart. I really dont watn to format i hope there is some way of fixing this.

i have fixed this problem. instead of repairing i installed on the same patron and didnt format and told it to replace the windows thing. to me it seemed to be the closest thing i could do to keeping my files. its installing the windows raight now i'm shure glad i got it working.Case Closed