Hey guys!

Not sure if I'm in the right place to post this, if not please kindly redirect me.

So, I've recently purchased the parts to build a fairly top of the line gaming rig, have set it all up and had it running normally for about 3-4 days, now every now and again the computer won't turn on. It usually only happens on cold boots but has recently happened with restarting aswell.

The only way I can get the computer to turn on is if I turn the power supply off at the back, wait a few minutes and turn it back on (usually 50/50 chance that this works)

I have:
-updated bios to the latest version (0602) with no luck in fixing it.
-replaced the CMOS battery, aswell as reset the bios about 3-4 times now.
-checked the psu voltages, without any obvious problems (12.096v, 5.00v, 3.328v, aswell as Vol_CHAB=1.346v and Vol_CHCD=1.331v)
-I had previously had it overclocked via the ez tune wizard in the bios, with no negative side effects that I could find, so I redid the wizard on the last bios reset.
-have tried disconnecting the 4pin to the cpu as I read in one thread that if the 12v rails aren't identical that it could cause damage when the 8pin and 4 pin are plugged into the cpu socket on the mobo.

After I replaced the CMOS battery, it had about 5 cold boots working perfectly fine but then started faulting again.
I've ordered a 1kW psu to replace the 850w as I'm really hoping that its the problem, but I'm honestly not even sure anymore as the voltages are damn near perfect and its still got the issue.

If anyone could shed any insight as to why I've got this fault or what I should do I will be very grateful, if you need any more info feel free to ask.