Computer screen occasionally remains blank upon startup

[vladko10]

So as the title states i'm having a wierd problem... It mostly happens when I turn it off and immediately back on (restart) though if I turn it on after being off for a couple of hours it usually boots up without any issues. When it decides that it's not going to boot up i unplug the hdd for a couple of seconds and when i turn it on it usually works. When it doesn't boot up, I noticed that the HDD is spinning but i can't hear nor feel the heads moving that's why i decided unplugging it and plugging it back in and so far it seems to work, but it's annoying . Any idea why is this happening? 

Specs:

Mobo: Asrock 990FX Extreme3
CPU: FX-8320 OC to 4.20 GHZ on 1.200 vcore
HDD: Seagate SV35 1TB
RAM: HyperX Fury 8GB 1600mhz 
PSU: Corsair VS450
GPU: Sapphire R9 270X Vapor-X

Thanks in advance!

[Sankster]

tried turning down OC?? 

[vladko10]

I did actually it was 4.4 GHZ but i turned it down to 4.2 and increased the voltage to 1.215. The last time it failed to boot was yesterday, today I turned the PC on twice and it worked every time :\