haveing problems with this game

I'm upgrading soon, but for now all I got for games is my athlon xp rig. its realy realy old, only a 20gig hdd so I dont have alot of games on it, I got a geforce 2 gts video card and I just put a new hsf on it. i'm prety sure everthing went on right, and its bigger and beter then my last hsf. I got 512 of ram and the game i'm playing only needs 256. whats going on is, after 30 mins or so of gameplay it will just kick my out of the game and back to windows. its windows 98se, and the game is enter the matrix.

Thanks, the game updated my direcX when I instaled it. Its the newest game i'v put on there cuz most everthing els i'v just been playin on my laptop. well, I got a copy of xp sp2 so i think i'm just going to buy a new hard drive and install it. 20gigs is rediculus. lol for now i will clean it up and make sure my eqp is all working properly.