The battery is booting up, running and charging when charger plugged in.
The laptop will run when charger removed and battery discharges as expected through use.
When turned on with no charger, the laptop boots up and will stay on until user pin is entered at which point the desktop comes on for a split second and then the Laptop loses power without shutting down.
Any advice welcome!
Sounds like the battery may be going bad soon and needs replacing. One sign of this is that they won't hold enough power to startup and run the device. Even though they will run it once on (if the charger is connected when starting). I suggest you replace the battery.