Sometimes my computer wont start

[Mk22]

Hello,
I have just built this computer and came across an odd problem. Sometimes when i try to turn on the computer only the lights come on and fans run but my keyboard, mouse and monitor wont come on. I then hold down the power button untill it shuts back off. I then hit the power button and suddenly everything starts normally.

Specs
mother board- Asrock 970 estreme3
cpu- AMD PhenomII x4 965
memory- 8g x2 Gskill sniper
psu- rosewill 640w
video- xfx radeon hd 6670

I have used a few different video cards thinking that could possibly be the problem but it still persists.

when it starts i can play games, stream videos and anything else all day long, but if i turn it off or allow it to go to sleep mode i will have this problem when i try to turn it back on.

 

[alyoshka]

Try changing the PSU to a better one.... it's most probably no giving the correct amount of current in one of the wires....

 

[aicom]

First try updating the BIOS. It's possible that the BIOS has a bug preventing it from waking up properly.

Here's the link for the Windows BIOS updater
ftp://174.142.97.10/bios/AM3+/970%20Extreme3(1.70)WIN.zip

 

[unksol]

blaming the PSU makes ZERO sense. Currant is based on load. The PSU could only supply the wrong voltage. NOT currant. Need to know the model. but VERY unlikely considering rosewill qualify has gone up and your system load is so low. you need to swap components to diagnose. probably the motherboard. Or bios as said above