I had a pc with windows 2000 NT. I tried to load Xp on the the Hard drive. I did it by putting my hard drive in a pc that already had xp on it. It loaded fine, but when I tried to put it back in the other pc it wont load. I cant get to bios or anything. Help

First off a version of XP will only run on the computer it is licenced to.
You just can't copy it off another computer.
Sorry if I misunderstand your meaning.

Did you delete the 2000?

Are you saying now when you power on "Nothing" happens? No BIOS POST? No nothing? Errors? Beeps?

its impossible to just transfer the Windows files from one computer to another...u have to run the installation on that particular drive if u want a seperate version of XP installed