Are you re-installing with a genuine Windows XP disc or is it a System Recovery Disc that came with your comp?
When re-installing are you booting from the disc?
If you haven't been into the BIOS previously to alter anything I would leave it alone just for now.
At the moment the only way you can see what make your hard drive is, is to open your comp up and have a look inside.
-------------------- As I lay in bed gazing at the night sky, dumbstruck by the awesome beauty of the heavens. I couldn't help but ask myself.....Where the hell has my tent gone ??