I have to ask you if you have any Data on this PC you need to Keep, and if you do i would recommend you connect your Hard Drive to you other computer and copy all the important Files off, and Run an Anti Virus Scan on them just to be safe.
Then once you have all your files backed up, i would suggest you put the Drive back into its computer , and format and Reinstall windows, as this will work faster than trying to take apart your windows install bit by bit.
if you have any problems while installing windows i would expect you might have a faulty hard drive. As its a windows 2000 system i am guessing its quite old, and Hard Disks don't last forever.
If you need any help with moveing you HDD to a new PC to back up the files ill tell you all you need to know, if somone else dosent beat me to the punch
