Sometimes my pc could not boot up (could not boot the monitor- if I turn the pc off and turn it on right away, no problem. but if after turning it off and leave it for ten minutes, then I could not turn it on). I think that maybe it is the problem of power supply or video card. Do you know, besides changing power supply or video card, is there anything that i can do to fix this problem, like change the CMOS setting?

Thanks for your help in advance