I'm not very knowledgeable about laptops, I only mentioned the terminals thing because I've heard others have this problem.
If you can borrow a friend's (or computer store's) battery, and find that works you've found your problem. A laptop battery should last from 1 to 3 years though, so this is an unlikely cause in your situation.
I assume you charged the battery (joke, sorry but I had to say it).
Sorry I can't be more help. Someone else will have a better idea.