Have you tried a "HARD reset"? I had the same problem and couldn't get anything to work, even opened the darned thing to check the connections. I'd done what I thought was a reset, but forgot one crucial step...which was to discharge it without the battery in. Once I did it correctly, everything went back to normal. Hope it works for you!
To perform a hard reset, follow the steps below.
1-Unplug the AC adapter from the notebook PC (and remove from any port replicator or docking station if you are using one).
2-Remove the battery from the notebook battery compartment.
3-Press and hold down the power button for about 20 seconds.
NOTE: Holding down the power button while the computer is turned off drains any residual charge in the capacitors.
4-Insert the battery and plug the AC adapter back into the notebook PC.
5-Press the power button to turn the notebook PC back on.
You may see a recovery console option come up. Just skip this and choose the option to boot into Windows normally.