I have a notebook two years old,and it refuses to boot. For a while, the battery life getting shorter and shorter, until it suddenly started not charging. Oddly, the laptop no longer works with the charger plugged. Is it so than a laptop can not work on AC power without a battery? Or is there more to it? When I test the charger with a voltmeter it seems to work if I connect it to the laptop starts the first red light that otherwise fire and then later green flashing red and then stop. It is a question about 8cell lit-ion battery. Is it enough if I buy a new battery ? How to Choose a Battery? Many laptop companies has different batteries, and some laptop companies have different batteries for different models,such as: HP EliteBook 8760w Battery , DELL Alienware M17x Battery . So how to figure out which is mine? Any suggest is welcome.Thanks in advance.