I have been having problems with Source Engine lately. First of all, my HL2 will start up but when at the loading screen, it will exit. Also in CS:S, I have been getting below 20 FPS on 640 X 480 with low details. I have a 1.6 GHz P4 Willamette 256 KB L2 Cache, Intel D845PT AGP 4x with outdated BIOS ( ), GeForce 5700 FX LE with second latest drivers, and 768 MB Ram with 2 2 2 5 timings ( i think ). I have seen people with much lower specs run it at 60 FPS on 1024 x 768 with medium details. Could this be a result of my windows being destroyed (basically)? Should I format and reinstall XP, or any other suggestions?