Why won't my dell d610 power on?

My d610 laptop won't turn on. When I plug in the adapter, the battery light flashes green every 20 seconds or so, but nothing happens when I press power. I tried taking out the battery, same result. I checked the battery, all 5 green lights come on when I press the button. I took the case off and the inside is pretty filthy, but I'm scared to touch anything. I've done a web search for the problem, but everyone else seems to have red flashing lights or the computer will start but only for ten seconds, mine won't turn on at all. Is my PC just dead?