Precision M90 Powerup Problem

The problem started about a week ago. I'm running vista. i rarely shutdown, i just put the system to sleep. when moving between work and home. when i get home, i open the lid and continue. normally, I'm in transit for an hour and a half. on this day, my laptop was in my bag for about four hours. when i eventually opened it, the power led flashed and it went off.

now when i try to power up, the power led comes up, the HDD led flashes, the cd drive works, i hear the hard drive spinning, but thats where it stops. if i press the power button again, the bluetooth led flashed there's a click, and it goes off.

when it started , i found that by tilting the laptop to weird angles, or repeatedly preesing the power button, it would come eventually boot. now it won't.

i've tried most of the possible solutions, swap the ram (3gb) remove the battery, reseat the abttery - no dice.

as per warranty - i'm in Nigeria and precisons are not supported down here.

this happened once before, and after a full recharge, the laptop restarted. but this time - no dice
any ideas?