Game runs choppy, help would be appreciated

[imdashep]

First, the specs

2.02 GHz
1 GB Ram
ATI 9600 128

The thing is, I've run graphically intensive games (Star Wars Galaxies, Americas Army, etc) on it without any lag whatsoever. However now when I play this game, its really choppy. Fine for a few seconds, then for some reason it suddenly freezes for half a second. So I lowered graphic settings to minimum, and it still did it. Please tell me it isnt my computer

[threatlockz]

it's prolly your drivers. update all mobo/chipset drivers, as well as those of your graphics card. get latest directX, ...