My pc freeze, my monitor goes 2 pwrsave when using opengl appz

My computer: msi k7 master
athlon xp2400
geFx5200 (had the same prob with 4600ti)
512mb DDR

My computer locks up when trying 2 start
Counterstrike 1.6 … It goes straight to powersaving mode on my monitor… I have changed refreshrates, accelerations, directx drivers, every nvidia driver, checked the heat… changed mainboard bios, Graph card bios, agp drivers etc etc… still does not work…

only if I format the HD , it works for like 3 or four days… and then back 2 normal… and sometimes it just works out of the blue…

THIS is driving me nuts… and my counter strike clan too… plz plz plz help;)