Pc fails to boot

[gokuz]

Hi,
I have the current pc configuration
Mobo:ASROCK p67 Fatality Performance - 2.20 bios
CPU: 2500K overclocked to 4.3ghz
RAM- 8gb
SSD- 128GB crucial M4
GPU: saphire 6870 1GB
Power Suply :Corsair CMPSU-550VX - https://www.pcgarage.ro/surse/corsair/cmpsu-550vx/
I had a saphire 5850 untill about 1 week ago when my problem first started to apear.
After a nights sleep when i try to boot the pc in the morning for the first time,pc starts i can hear the vents runing,the lights light up,but pc doesnt show anything on screen....screen is completly black.It doesnt boot into windows because i dont hear the windows start sound.I have been runing my system overclocked since day one,wich was in april this year,no problems with it.I can run prime95 for hours without any problems,my voltage in full load goes to 1.37.This problem apeared about 1 week ago when i got my 6870 to replace my 5850 video card.I was thinking about power suply,but the 6870 should draw less/or the same power as the 5850,and when i get into windows everything runs good(no pc restarts,no blue screens).To get my system booting up i need to restart pc few times,or unplug my power cable from the power suply,than start it again.....could it be my overclock ?or just my power suply runing low on juice.
tks

 

[Dangman]

Turn off your OC and then see what happens.

Also, follow the stickied "Basic Troubleshooting Guide" on what to do when the PC does not POST.

 

[gokuz]

ok i think i narrowed down the problem,just before i got the video card i also did a bios update went from 1.30 to 2.20 the latest version from asRock site.Trying to narrow down the problem i went to 2.10 bios and with this one i get this issue everytime i shut down my pc,no cool down time is needed.If i shut down my pc,than try to turn it back on screen goes blank.So i wanted to revert back to 1.30 my stable bios from before,i flash my mobo,than after i restart i get these errors.:

Pc boots just fine,but i get these errors.....flashing was down from usb stick from within the bios,and i tryed several versions of the same 1.30 bios,also tryed other versions:1.10,1.20.Everything except 2.10 and 2.20 gives me these errors.Pc boots fine after i get the erros tho.
tks