Big Boot Up Problems

Help!

The other day my Dell Latitude notebook failed to boot. Not even the fan started. All I got was a little green power light. Tried all combinations of removing battery / AC only etc. When there was no battery or AC, the green light died. Tried to start again – the capslock key flickers to life briefly, as does a second green light below the power light… then it’s just back to the green power light only. No fan, no screen, no sound, nothing.

Had to go out at that time (which probably saved me from throwing the thing out of the window). Came back hours later and hey bingo, the problem had disappeared. Normal service resumed.

Days later the problem is back, except it hasn’t solved itself after a few hours this time.

Any advice?