My mom has a 640m that she got a little bit over a year ago... and that she never runs off battery. That battery seems to be dead or something. If you unplug the AC adapter while the computer is running, the computer will turn off. If you unplug the AC adapter and then try to turn the laptop on, it won't boot. But Windows reports the battery as being 100% charged, and if you push the little button on the battery, all the lights go green. Any suggestions? Battery? System board?