computer start,when main plug switch on

[keeran]

I have following configration computer
Pentium dual core E5300 processor,320GB Hard drive,2GB RAM With Gigabyte G41M-ES2L Board.win xp sp 2.
    I have been facing problem very strang. My computer start automatically,when power plug switch on  without pressing start button on it, and shutdown suddenly. After then i start the computer pressing start button, it doesn't start.

[Bromide]

Perhaps there is a short circuit in the Start button wiring, so that the Start button is always "On". This would make your PC start as soon as it is plugged in and then stop after 4 or 5 seconds as if you were holding the Start button.

To test this, unplug the PC, open the computer case and find the 2 small wires that connect the Start button to the mainboard. Unplug the wires from the button or from the mainboard [Remember exactly where they were so you can reconnect them!]

 If you have an ohm meter, test to see if electricity can pass from one of the wires to the other without pushing the Start button [if so, the button is bad]. 

As a further test, plug in the PC while the Start button is disconnected. If it still starts by itself the problem is somewhere else. If it does not start the button may need to be replaced.

[keeran]

 As per ur instruction,i disconnected the push button wire and then plug connected to the  power suplly.At that time cpu fan ran for few second.and also CD ROM Drives LED Bllinking.
Thanking you.

[Bromide]

So, with the Start button disconnected, does the computer behave at all differently from when the Start button was connected, or is it just the same?

There is one more way to test the Start button.  With Start button disconnected and the computer connected to a power outlet, reconnect the Start button for only a brief moment, not more than 4 seconds, then remove it. This would be like pressing the button, even if the button is actually stuck in the ‘pressed’ position. Does the computer start? If so, install a new button. If not, the problem is elsewhere.

I’m afraid I have no other suggestions for fixing the problem. I hope this solution works for you. Good luck.