Hi Need some help, I have an inspiron 5100 that I bought couple of year ago. few month back I noticed that the machine is not charging the battery when the laptop is on. as sson as I shut down and turn off teh laptop, teh charger stats working on the battery. So I don't beleive it is a battery problem but rather a charger one, I'm wondering if someone know if it is a software related and how to fix it.

thanks

Check very carefully for full contact from the charger points, and the best way to clean them is with a pencil eraser, followed by denatured alcohol and a queue tip. The contacts do become weak or bent, which can cause the problem.
There is no software that affects that model, but there is a chip in the battery that counts the number of full charges. Onces it reaches that magic number, it stops further charging even though good otherwise. This is to prevent fire and other damage as the battery ages.
Otherwise, you need someone with experience using a soldering iron, to replace a couple of doohickies inside the case.