Computer Keeps Restarting

Okay, here it goes:

My computer runs on XP, i always install the updates so i guess it should be the most recent service pack.

A few months ago my disk drives crapped out. (i did check and try all solutions i found online for this problem)

Anyway, after installing updates for WoW, which i already had installed for at least a year, my bro was playing and he shut off the computer without even logging out (press and hold). Now my computer wont start up. or rather, thats all it will do.

I have tried going into safe mode, and from "last good configuration" and restarting normally. however it always goes to the screen where its loading XP, and then starts over. and repeats. and repeats. The computer does say that there is a problem with the hard drive (after i go to the f10 settings)

My computer is about six years old.

if there is anything else you need to know, ill try to post it immediatly.