I have 2 of these when they failed i was told MB was dead, i stuck them in a cupboard for 3 years. today when cleaning i found them and decided to see if i could get them running.

Replaced the CMOS BATTERY. powered on holding the FN key down and closed the lid still powered up 10 mins later one started beeping then the other.

switched off power button open screen then press power button and both booted up showing date as 2000 reset date in bios ( F2 on power up) saved update then rebooted straight in to windows.

battery is a 2032 little round battery pack of 4 cost £3 .

time taken 1 minute to remove backplate and fit new battery.

before i would hear 1 click as i pressed power switch and only fan in bottom was running.