PC won't power up. Please help

JohnXS

Distinguished
Aug 8, 2011
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18,510
Everything was fine and my PC was working perfectly. 
I shut it down, went with friends and when I got back home and pressed the power button of my PC, it powered up and the yellow light came up ( the red light didn't ) then after 3 seconds the PC powered down!!!
after 2 seconds it powered up again by itself i didn't do anything then powered down again and so on.... Till i shut the power supply down
I tried reseating the RAMs and cleaned everything but nothing happened
I also noticed some LEDs on the motherboard during the powerup , they were 3 green or yellow idk and a red one
So.. I don't really know what's going on Please help me ):