Solved Computer randomly shuts down abruptly, then reboots

[torninja]

After moving to a new home, my computer started misbehaving. It spontaneously restarts, no error message and no BSoD. The computer abruptly shuts down as if someone pulled the power plug, then it reboots.

Important clues:

• The shutdowns happen at completely random times, nothing seems to trigger it
• Sometimes it happens during boot (which makes me think it is a power issue)
• Unchecking "Automatically restart" does not give a BSoD, shutdowns continue to happen abruptly

Things I have tried:

• Memtest86 ran 5 passes, 0 errors
• SFC /SCANNOW did not find any problems
• chkdsk command found no errors on any hard drive, including system disk
• Running two antivirus programs (malwarebytes/adaware)

 

[oscer1]

hi,

open the case and check all connections make sure you unplug the computer from wall first and hold the power button down for 10 seconds to let residual power drained. then unplug and plug every connection to make sure they are seated all the way.

 

[torninja]

I took the power cord out and held the power button for 10 seconds, then I gently unplugged all cables inside the computer and plugged them back in, one at a time. Now I get no picture from the GPU, and I have no onboard graphics.

Without a signal from the graphics card I can't determine if the boot is successful or not.. I am out of ideas

 

[oscer1]

You have to remove card to get onboard graphics.

 

[AddRAM]

Just start over, there`s no reason you shouldn`t get a picture using the graphics card.

Check every connection again.

 

[torninja]

Sorry for late reply. Turns out it was *drumroll* the 12v ATX power supply cable. It wasn't all the way in, which caused a power failure since the processor sometimes lost power. Thank you so much oscer1!

 

[oscer1]

Your welcome glad you found the problem