*bump* 
Sorry for bumping this thread, but did you find the solution to this problem yet? I'm having the same problems as Carlitoboy. I doubt it's a hardware problem since i'm playing really demanding games like Supreme Commander, World in Conflict, S.T.A.L.K.E.R. and Battlefield 2 and they run quite well on my machine.     
specs: 
AMD Athlon x2 3800+ 
Asus M2N4-SLI 
2048 GB DDR2 RAM 
Club3D GeForce 7950 GX2 1024 MB RAM 
Western Digital SATA II 250GB 
Creative Audigy 
Windows XP Pro SP2 latest patches e/a 
Running Lock On 1.2 (but this error also occured with 1.0, that's why i patched LO).   
I've tested the low settings. it seemed to work, so i was really happy flying around in my warthog, but it just crashed on me. Again.