I have a Compaq Presario 1200 (12XL410) laptop that has a questionable
battery. It seems to work. However, if you leave the computer alone
for a few hours and then try to start it, it will go from reporting
100% charge to 0% charge (obtained using the battery's built-in
lights) before Windows even loads.

Here's the weird thing. The battery still reports 0% through the
lights on the battery itself, but as soon as you plug it in for about
five minutes, it will report 100% again. If you unplug it, it runs
fine for several hours.

It seems like it needs to be plugged in to "remember" that it's
actually charged. Is there any way to fix this? I don't want to buy a
new battery!