To add to rj713's answer, you could try one more step which is to remove the battery, unplug the unit, and hold the power button down for a full 30 seconds (1 Mississippi, 2 Mississippi) then put the adapter back into the laptop and see if it powers on. If this does not work, there are only two answers:
1] Dead power adapter (easy) -universals are sold at many local places
2] Damaged internal parts (hard)
For the second answer, generally the power port on a laptop gets abused quite a lot with plugging and unplugging, pushing it to hard, bumping it while it's plugged up which jams the internal components pretty bad.
I see that this is an older question, so I hope you have your problem fixed. My answers are for archive purposes if you have :]