I have an Intel 3.0 GHz with 2MB cache , an Intel 945 PVS Mainboard, 1GB Kingston Ram, and a 6600 GeForce VGA (Leadtech), and i played all the games that has already been mentioned ( Battelfield 2 , Fear, Sniper Elite, Doom3) with the highest graphics quality , and found no problem.
You better change your PCs.