In order to correct problems with the battery's power management software, follow the steps below.
1. Access the "Device Manager" .
2. Expand the Batteries category.
3. Under the Batteries category, right-click the "Microsoft ACPI Compliant Control Method Battery" listing, and select Uninstall .
WARNING: Do not remove the Microsoft AC Adapter driver or any other ACPI compliant driver.
4. Then 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.
5. Restart the computer and Windows will re-detect the "new" hardware and install the correct drivers for the battery hardware.
Or...If the devices aren't found and installed on restart...
On the Device Manager taskbar, click Scan for hardware changes .
Alternately, select Action > Scan for hardware changes .
Windows will scan your computer for hardware that doesn't have drivers installed, and will install the drivers needed to manage your battery's power.
This should cause the battery to charge correctly again...UNLESS the charger is faulty.. In that case, replace it. Or...as the others have said, if the battery has simply gone bad, then it won't make a difference and the battery will need replacement.
Hope this helps.