PC does not boot

[bjlukas]

Guys

I have had a recurring issue with my PC, but the symptoms have changed over time.

Issue became more frequent after I changed the HDD to SSD. I had some similar issues before, but with less frequency.

Problem was that it would continuously reboot before entering BIOS.
Sometimes (maybe about 1/8) it would go through BIOS and then work fine, with no issues at all.
Other times (maybe 1/4) it would not reboot, but not go to BIOS either. There is no MB beep at all when this happens (fans and MB lights on, but no booting).

I went through the troubleshooting guide on this forum, and tested systematically with the most basic components, moving up.

Results were:

CPU, HSF, PSU only (no mem or GPU) 8 short beeps & then reboot (although # beeps isnt always consistent)
CPU, HSF, PSU, MEM (no GPU) fans & lights on, no beeps
CPU, HSF, PSU, MEM, GPU: as above, no MB beeps

Now consistently it does not boot. It hasn't got through to BIOS since I started these tests.

I'm guessing its either PSU or MB. I will test with another mem stick, but don't have access to the other components to test them.

Do these symptoms suggest MB over PSU or vica versa?

Any help would be appreciated.

System:
PSU Corsair 620w
MB: GA-X38-DQ6
CPU: Int Q6700 775 2666 BOX1066 8M

 

[bjlukas]

Ok, so I tried to clear the CMOS, as I had made some changes to the BIOs to enable USB keyboard.

The rebooting has stopped.

Now the PC boots to the MB splash page about 1/4
It turns on with no beeps or video 3/4

I can't get past the MB splash page. Should the USB keyboard work at this stage? Or do i need a PS/2 to input at this screen?

Thanks