"Plugged in, not charging" [XPS M1530]

Hello all,

I have had my XPS M1530 laptop for about 11 months now.  As of recently, my battery does not charge.  When I hover over the icon in my taskbar it says, "22% available (plugged in, not charging)".  The only time that it seems to ever attempt to charge is when I unplug the adapter from the laptop and proceed to plug it back in.  The battery icon goes through the animation of charging once, and then goes back to the "22% available (plugged in, not charging)" icon.  I am unsure to whether the problem is with the software, AC adapter, or my battery.  My OS is Windows Vista.

I have tried all of the following:

• Tthe battery out and putting it back in
• Restarted/shut down my laptop
• My AC adapter is plugged into a wall outlet 
• Swittching between power plans
• Switched AC outlets
• Updated BIOS to A12

Please help,

Thank you!