Problem when restarting games on my pc

Yo people,

I recently installed FEAR and STALKER onto my comp, and am having problems when restarting the games. When i first install it, it works great, shaders and textures are orgasmic. But when i shut down the program and reboot it, it is like I am running the game on Windows 95. I actually have to reinstall the games to get them to run well again, but then comes the obvious problem of having to end the program at some point. I am literally dumbfounded by this and if anyone could offer some insight that would be great. I almost punched a hole in my wall while trying to fix the problem as well.

Currently using :
ATI All in Wonder X800XT
AMD Athlon 64 3500+
1 Gig of Ram