Moving Hard Drives

I would like to move the hard drives on a Win2k machine to another machine. The last time I did this the system told me that because a new controller had been found, I would have to reinstall win2k. I’ve done this many times with other versions of windows, during motherboard upgrades, and never had a proplem. Am I missing something here??? .. This should be a simple upgrade, and I don’t think I should have to do a complete reinstall.