Computer wont boot when 12v 4pin is plugged

Dpuk

Honorable
Aug 14, 2013
1
0
10,510
Yesterday everything was fine and my system ran smoothly., but suddenly CPU stops and everything went out.

when i connect my 2x2 12v pin CPU starts up, fans rotate, lights in mouse keyboard but suddenly everything stops after 2 seconds without booting.
Monitor remains black.
i tested with another PSU but still the same problem.

when i unplug it fan rotates. please help me to get outta this...
 
Solution
Without the 12V EPS it will power but not POST. That's normal. If its not working when its plugged in and you tried a new PSU its either a faulty GPU or RAM module or motherboard.