A8V Deluxe / ATI 9800 Pro-XT / HL2 AGP issues

[Nuke Waste]

After wrestling with my A8V and K8N Neo2 I finally got the ASUS board to work... kind of. The board is rock solid now after selling my GF 6800NU and throwing in a buddy's ATI card. The problem is, whenever I try to play HL2 or CS:Source, I get random lock ups and crashes. Has anyone else had this kind of problem? I'd like to get my own 9800 and soft mod it, but if I can't get the ATI drivers to work there's really no point.