Laptop battery won't charge

[JJBuffone]

Hi, I have an IBM Thinkpad R50e that I received when I was a freshman at college. For some reason the battery won't charge, although it continues to work with the A/C plugged in. Should I just get a new battery or is there another way around that. Thanks for the help in advance!

[RodeoBlue]

Laptop batteries have a life span of usually 1-2 years, I've had my laptop for 2 years almost and I've burned through 3.