My PC randomly shuts off and won't turn back on for hours

[AbideSam]

My PC will randomly turn off and it won't have power for up to two hours. I'm not sure what's causing this, I have reason to believe it may be the motherboard but I'm not sure.

My specs
CPU: Intel i7 4790k
Gpu: gigabyte gtx 980
Mobo: MSI Z97-G45 Gaming
16 Gb corsair vengeance ram
Corsair h100i liquid cpu cooler
Corsair 750w PSU

 

[Mac070]

Make sure your water cooler is still working right . It might be broken and your chip could be over heating . Uh but my idea is the power supply . Of its a cx then its crap.

 

[ingtar33]

power supply is the biggest suspect; that said the symptoms actually more closely align with something overheating then a bad psu. it's just you have a junk psu and those can act similar when they break too.