I have an HP Pavilion N5440 laptop that I'm working on. The front lights all come on but it shows nothing on the monitor. The front lights I'm talking about are like the same buttons that are on a CD player. Looks like reverse symbol, fast forward symbol, eject, sound, etc. However, I do not see any other light come on such as an on/off button light. When I use the power adapter with the laptop and hook it up to my monitor, my monitor actually turns off. (When I hook my monitor up to another laptop or my desktop, it works fine.) I've tried with the battery in the laptop, with just the adapter in the laptop, and with both adapter and battery ... and end up with the same results. It turns off my monitor. Is this the result of a bad battery or could it be turning off because of a short...to protect my monitor?

Oh..and... is there any way to check a battery before buying one?