Good Day Smurfy1020,
My name is Carlo, I'm an Independent Advisor and community member like you.
I am also using Windows 10 pc. Let us work together to sort this out.
Here's the steps you can try.
-Click Start, type CMD and run it as administrator
-Copy and paste the command below and hit enter.
Sfc /scannow
Wait until the pc finishes scanning and repairing any corrupted system files then proceed with the next command
DISM /Online /Cleanup-Image /RestoreHealth
Restart and check if you can now lock your pc using the Windows key + L
If the issue persist perform Repair Upgrade , this will re-install the Windows without affecting your files and apps, it will repair and replace any corrupted system files.
Step 1: Download Media Creation Tool from Microsoft.
https://www.microsoft.com/en-us/software-downlo...
Step 2: Run MediaCreationTool.exe.
Step 3: Choose "Upgrade this PC now".
Step 4: Select "Keep personal files and apps".
Step 4: Let it install
I hope the information above helps. Please let me know how it goes.
Have a wonderful day ahead and stay safe.
With Warm Regards,
Carlo T.