Does the power block get hot when you plug it in?
Can you power the laptop with the battery out and ac power only??
I have not noticed (my laptop is at home, i'm at school currently, but i was working on it last week) whether or not the power block warms when I plug it in but I do know that taking the battery out and plugging in the charger doesn't provide any response.
Usually, there will be a small plug icon on the front panel screen (where it shows the time) telling me that the battery is charging but, that is not there when the battery is in and I'm trying to charge it.
I feel that my only two options to troubleshoot this are to buy a new battery, charger, or both but I want to confirm that I have done everything that I can before I plunk down $100+.