Purchase a new CMOS battery, just in case the other one is dead, install it, then perform the following steps to hopefully get the system charging again. (Of course, this is assuming the laptop's main battery is still viable.) Shut down the computer, unplug all power cords, remove the battery, then depress the power button for 30 seconds. Replace the battery making sure all connections are solid, then plug in the power cord. Hopefully things are good.

If the main battery is no good, then the system may not charge correctly till you get a new one. In that case, you have to consider whether it's cost effective to purchase a new battery vs getting a new computer.

Of course the question comes up... What knocked the CMOS battery out of its snap-in holder? I've not seen that happen unless someone actually removed in manually.

Hope this helps.

Grif