Hi,
do you have any light going on when trying to power on ?
First I would remove the battery and try to power on with the plug only (if it is ok, shut down computer and try with battery.
If you still get nothing: Remove the battery, plug and memory, then press and hold power for about 10 sec. Replug and try to start without the memory. If you hear beeps or get a blank screen. Unplug the computer, put memory back in and try to boot.
If you get nothing, you probably have problem with power or motherboard and need to be taken in a shop to look at.
Keep in mind that repair will cost about 300 $ from there and it might not even be able to be repaired.
Might want to consider buying a new one.