Inspiron 630m - Laptop won't start when battery is inserted

When the battery is out and I just have the AC adapter plugged in, everything works perfectly. When I insert the battery (while the computer is still on), the power meter indicator goes from the plug (On AC power) to the lightning bolt superimposed on a plug (Charging, 0%). But after a few seconds, the computer turns off suddenly and won't come back on. The green light on the AC adapter, which previously was on, goes dead. Even after I remove the battery, nothing works until I unplug the AC adapter from the wall and plug it back in.

Does this mean the battery is dead, or could it be something else? I'd hate to buy a new battery ($166 for a new one!), only to find out that something else is the problem. The battery was performing fine until the day this problem came up. When I hold down the indicator button on the battery, it comes up with 4 green lights out of 5. I'm running Windows XP Home.

Let me know if I've missed any information that may help. Thanks!

Message Edited by kenthu on 12-10-2007 08:27 AM