PC not starting after pressing power button

[wonderboy001]

i press the power button....the smps fans starts for around 2-3 seconds and thats it !
nothing happens....
i checked all the external and internal wirings but to no avail !

what should be the problem ?
the SMPS ???

[Rawko]

You may or may not see a light on the back of your PC depending on the kind of power supply you have and the exact cause of the problem. Some psu will run its fans (also case fans if it has a line for them) and lights for a bit without turning on the system, and may stay on after the system powers down (for a minute or so) to cool off the pc completely. In order to resolve your above issue, you need to check out the below links mention.

Starting my computer without a power button

Computer doesn't turn ON when pressing power button

Turn on computer without pressing the Power button

Computer Won't Resume From Sleep with Power Button

Hope so it may resolve your above issue.