What do you want to do with this PC that was given to you that you can't do already on your Amigas? What speed and memory is the PC? If it is at least 500mHz or faster Pentium 2 or 3, it is fast enough to run WinUAE/Amiga Forever. Probably your best bet for non-Amiga, non-Windows OS is SuSe Linux 9.3 as others have suggested.
