hi guys!!! well, i`m having a very, very weird problem with my p.c. and so far it`s driving me mad.

i have a pc with a 2.4 pentium processor 512 of ram, and an ati 9800 card. Lately i`ve been having this very weird problem that happens when i play games, with nothing else. When i play a game suddenly the hd resets and windows restarts, this always happens when i`m playing and it doesn`t matter if i`m playing a very demanding game (like tomb raider anniversary) or a not very demanding one (like scratches). this always happens, so far i have reinstalled windows just in case there was something wrong with it and it didn`t work, i have the latest drivers for the card, the last version of direct x, i have checked the temperature of my computer but there is no overheat problems, no problems with the power supply, i checked all the connections and re inserted everything like the processor, the memory, i reconnected everything, checked the wires but nothing has solved the problem. Sometimes the problem has a variation; it happens that suddenly the hd resets as i already explained, but for some weird reason windows doesn`t so the game stays there and freezes for a moment and the hd suddenly wakes up and then the game continues running like if nothing happened, but this is not very often, most of the time when the hd resets windows does it too. As i said the weird part is that this only happens with games, i also use 3d max, zbrush, flash and photoshop and i never have any problems with this programs no matter how demanding the program is or if i have a very complex 3d model i never have a problem. Do you guys have any ideas why this is happening?? i was thinking that maybe the hd is the one of the problem but is it really possible when i don`t have any problems as long as i don`t run games???

please help!!!

thanks!!!