your question is just too vague. We need more info.... Are you trying to say that when you plug in your laptop, it doesnt charge the battery? etc?
A common problem with laptops is tat the port where the power supply connects to the computer gets abused. The cord gets pulled on a few hundred times and it can actually break the contacts in the latop. You need to check and make sure that your power supply (ie: the cord and box asssembly that plugs intot he wall) is working. You can do that easily with a volt meter. If it is ok, and the laptop still wont power up, the problem is usually the connections inside the computer where it plugs in..... It's very difficult to fix, but it is possible. However, i wouldn't rust the repair to last very long. The proper repair is a new motherboard.