Had one of these come in today – customer had two, and both died in short order. Thought it might be a faulty docking station.
Symptom: Charge light works, but no power light or power switch function. Holding power button for >15 seconds causes the caps lock light to come on for a second or so.
Solution: Seemed to be to disassemble, remove the main battery and the CMOS battery. Power up the machine and get past the bios battery failure message, and hopefully back to normal. Possibly you’ll find yourself in the middle of Windows update – possible cause of suspicion??