My computer won't start up.

For about 1 month my computer would occasionally shut down while sitting un-attended.

But, would restart when the power button was pushed. It has been running virtually day and night since I purchased it new in 2009 in Saudi Arabia, (I am currently in Thailand). I installed a new battery and reset the PRAM plus cleaned everything internally. Including the vents to the power supply.

Afterward it started fine and worked for about 4 days and then shut down on it's own and would not restart even by holding down the Command, Control, Escape keys which had worked once before. I opened up the computer and checked all connections and then tried to restart but nothing happened.

There was no start up chime nor fan noise. I pulled the memory cards and tried to start the computer again. The memory beep worked just fine, so I know the start button and low voltage side of the power supply work.

The next thing I tried was observing the diagnostic LED's during start up. When I plug in the computer,

• LED #1 lights. When I push the start button,
• LED light #2 glows for a moment and then both LED's #1 &#2 turn off.
• LED's #3 & #4 never turn on nor blink.

If I unplug the computer and then plug it back in again,

• LED #1 lights again but as soon as I push the power button
• LED #2 lights for a second and then both lights turn off.

If I unplug and replug the power cord the #1 LED will turn on again but what is interesting is that if I hold the power button down, both #1 & #2 LED's stay lit until I release the power button. Then they both shut off again.

Does anyone have a hint as to what might be the problem?