Macbook late 2008 Battery...shows X on desktop but still works when unplugged

[eziolkowski]

I have a late 2008 Macbook. Recently the computer ran out of battery and when i went to go plug it in, it turned on but showed an "x" on the desktop. However, when I unplug the computer from the wall/magsafe cord, it still works! Help? What is wrong with the battery.

Also, when i press the button on the battery to show how much life is in it. The bottom light just blinks continuously

 

[Gav2k]

I have a late 2008 Macbook. Recently the computer ran out of battery and when i went to go plug it in, it turned on but showed an "x" on the desktop. However, when I unplug the computer from the wall/magsafe cord, it still works! Help? What is wrong with the battery.

Also, when i press the button on the battery to show how much life is in it. The bottom light just blinks continuously

http://support.apple.com/kb/TS1457