hobot

Usually you can run the automatic setup on a windows xp cd (install new windows, it finds it, asks do you want to repair?) and it will fix the mbr, or you could reinstall grub.

Mod Parent Up. He is right, I have never seen a fully installed WinXP be pulled from one machine and put in another without incident, though if you do not want to reformat, sometimes an auto repair will helo Insert windows xp cd; boot from it; goto install winxp; and if it is the same version of the install it should offer an automatic repair option. I have seen this happen when i change a video card, much less the whole computer.