Samsung laptop, purchased new in 2012. Windows 7 64-bit. 8GB RAM. Model NP300V5A.
I woke up one morning and woke the laptop. I had left it plugged in to the wall the night before. When it woke, it showed in the system tray the battery icon (no plug) with less than 15% battery. I checked the cord and it was plugged into a surge protector, into a wall. Solid connections everywhere.
Tried another position in the surge protector, directly to that outlet, directly to another outlet on another circuit, and on another outlet in another building. No luck. Still running solely off battery. The AC adapter has a transformer and the green light is illuminated when it is plugged in to the wall.
Eventually the battery died, and I couldn't get the laptop to turn back on. I brought it into Geek Squad who used a voltage meter to verify the AC adapter was working normally. He suspected mother board failure and sent me on my way.
I came home and plugged the laptop in to the wall. After several days now, the battery is fully charged. I can power on the laptop and run Windows. The system tray icon still shows battery (no plug) power icon, and indicates the machine is running on battery. The battery does not indicate it is being charged and does not stay charged as long as it used to nor does it re-charge from the wall normally... it's like it has to trickle in over extended period of time.
I tried to flash the BIOS with the newest available version, but the software wouldn't allow me, with a warning that it required an AC connection. So the computer thinks there is no AC adapter attached, just battery.
If I remove the battery, and keep the AC plugged in, the machine does not power on. If I remove the AC plug, and keep the battery in, the machine works fine.
I have re-seated the memory, tried just one stick or the other stick. Tried removing the hard drive, and tried booting from a USB live distro. Always the same: the computer thinks there's no AC adapter, just battery.
So. Any ideas? Could it be a faulty battery? Faulty adapter? Faulty motherboard? Software/driver problem? BIOS problem?