Question All Games keeps freezing and crashing! Help!!

[Soufiane11]

hello friend i have a oem HP Compaq 8000 elite sff with
Q6600 , 6gb ram DDR3 , GTX 750 2GB.
but since i install this GPU on my Computer all games freezes and crashes randomly but i can still hear the sound from them until they closes!
i tried everything from uninstalling drivers using DDU to updating nvidia driver,bios,windows 10! but nothing has worked!
i stressed test the GPU with furmark for about 20 minutes with no problems at all ! the temperature never exceed 63c°! please help my guys!
could vga cable or monitor causes this issus? because my monitor screen start tearing and showing some lines randomly long time ago before i install the gtx 750!! any idea??

 

[rgd1101]

full system spec? include make and model of the psu
what the cpu/gpu temp and usage?

 

[Soufiane11]

its a stock HP Compaq 8000 elite sff with original hp psu(240w) and gtx 750 2gb connected to a old monitor with vga cable
cpu never exceed 70c and gpu 65c at 100% usage!
i stress test both gpu and cpu no problem at all!! but its keeps crashing games randomly