Most likely thing is a bad motherboard. Try removing the battery and the CMOS battery from the motherboard if there is one, hold in the power button for about 30 seconds. Plug it in with wall power only, no batteries, see if that works to turn it on. If it does not, remove the RAM and try to turn it on. If there are no error beeps due to missing RAM, pretty much 100% it's a bad motherboard.