my laptop keeps locking.

[Jenic1]

the screen goes blue, it says locking and the whole thing shuts down. this happens when I am using it

[Lil_Boy_Blue]

Hi
PLEASE POST ANY RESULTS.
First:- Turn off the computer, press and hold the PWR button for 4 seconds.

Then - Leave only keyboard and mouse connected, disconnect all externally connected
devices such as Docking Station, USB storage devices, displays, and printers.
Unplug the AC adapter from the computer.

Next - Press and Hold the Power button for 15 seconds to Hard Reset.
Rinse and Repeat; Re-Connect the AC adapter.

NOW begin checking/testing/proving the Hardware is fit for purpose.
Power on your PC, press ESC (repeatedly), then F2 at the prompt.
Choose System Tests (Fast Test does a 4 minute hardware check).
AND/OR
HOW DO I USE DIAGNOSTICS?

HP PC Hardware Diagnostics is a Windows-based utility that allows you to run diagnostic tests to determine if the computer hardware is functioning properly. The tool runs within the Windows operating system in order to diagnose hardware failures. HP PC Hardware Diagnostics Windows comes pre-installed on new HP computers, but if not on yours, download here:-
https://www8.hp.com/us/en/campaigns/hpsupportassistant/pc-diags.html

[Jenic1]

The advice to hold down the power key for a few seconds to reset didn't help, maybe because I couldn't detach the power cable as I don't have a battery....  I downloaded the Diagnostics app though, and ran the checks. So far it is behaving!

[Lil_Boy_Blue]

Hi

Well I had a bit of a guess....  Matching products for United Kingdom (6)   

not knowing which G2 it is.

The reset of 15 seconds is to clear the memory and on-board capacitors etc to hopefully start as normal.

You should have backups and recovery media to hand nevertheless.

[Jenic1]

Thank you!