Does the green light on the charger turn orange when you plug it in? Because it might have been that you didn't actually charge it. The metal ring around the charger tip sometimes gets bent so that it doesn't make good contact. If you aren't getting a constant green or orange light when you plug it in, you might not be charging it at all.
That would be the easy fix. The real problem is probably much greater, because you probably know how to charge your laptop. The laptop doesn't need a battery to run, so if it doesn't start up while plugged in, you have an additional problem.
write back if you find that the simple things didn't work and you need more help figuring out a specific fix.