I have a Lenovo G500s. It came with Windows 8.1 pre-installed with the battery working fine. I've installed Windows 10 on the laptop now and suddenly the battery is not recognized anymore. It says "0% available (on power, battery is not charging)". The power led is blinking amber, which means according to the manual that "The battery has a charge of 20% or less and the AC power adapter is connected to the computer."
I tried another AC plug, plugging the battery in and out and rebooting Windows without any effect. Does anyone know how to fix this? after leaving the laptop on AC power attempting to charge the battery I've booted Windows again. It now shows still 0% but says "2 mins until fully charge" while the LED indication hasn't changed.