ok, i just got a new powercolor geforce 2 gts pro b/c my radeon kept crashing my system. but now, i still can't play my games. unreal, half life and CS all crash still. it's not blue-screening my ...

Just bought a DIY system and put it together today, everything runs fine except my screen has many vertical lines and windows will not let me increase my resolution (from 640x480) and color depth ...