5 inch wide white square appeared on my Windows 11 system screen

Two days ago this white square just appeared after I log in , and stays there overnight and I cannot find out how to remove it.
Ive heard that its not uncommon.Im using a fairly new Dell Optiflex 7010 mini PC thats never been a problem to date.I dont always shut the PC down at the end of a session but occasionally either invoke Sleep mode or just Log out.
Is there some bespoke software I can acquire that once installed will remove a screen problem like this? Or what should I do instead? ps I have no Administrator rights and have been blocked when I try to create an Admin password, something that baffles me.The Pc had been commissioned by a third party service provider whom I no longer deal with, but they insist they did not set me up with blocked Admin permissions and claimed not to know why! But they did have remote access for many months so Im not sure I buy their claims.

So Ive really got two issues that need to be resolved and will be very grateful for any advice.

Adrian Berridge aka Clactonpat

FYI- I did try to install the Free version of Revo Uninstaller in an attempt to fix the white screen but was prevented as it required me to be the Administrator!

It's the LG Monitor App intaller. It appears that Microsoft decided all on it's own to install this useless piece of adware on our systems! I saw it yesterday and couldn't track it down, but today I figured it out and uninstalled it. You can use the normal Windows uninstall to remove it.

You should be able to create an admin account using the bootable USB Windows media.

I've personally never had to do this, but I found this that appeared to work for several people.

1. Boot off the windows media
2. hit shift-f10
2. type c: hit enter
3: type dir hit enter
4. If you have a windows directory, that's more than likely your main hard drive.
If not, you may have to use diskpart to assign your drive a letter.. if you do have a windows folder go to step 5.
5. type cd\windows\system32 hit enter
6. type ren utilman.exe utilman.bak
7. type copy cmd.exe utilman.exe
8. Boot to windows
9. hit windows-key + u at the same time... (This should bring up a command prompt)
10. type net user admin 123456 /add (This will add a user named admin with the password 123456)
11. Type net localgroup administrators admin /add (this adds the new user to the local administrators group)
12. Type exit and hit enter

You should now be able to login as admin with admin rights using the password 123456.

Windows 10 and 11 users are reporting a graphical bug, and Google Chrome may be to blame ​

Wolfzz said:

Windows 10 and 11 users are reporting a graphical bug, and Google Chrome may be to blame ​

https://www.reddit.com/r/WindowsHelp/comments/1ulwzkw/this_white_blank_window_opens_itself_briefly

Click to expand...

This is the LG Monitor App Installer that MSC installed for us without asking a couple days ago. You can uninstall it using the normal Windows uninstall.

gunrunnerjohn said:

This is the LG Monitor App Installer that MSC installed for us without asking a couple days ago. You can uninstall it using the normal Windows uninstall.

Click to expand...

I Read that in Task Scheduler, clicking on the GoogleUserPEH folder on the left hand side then right clicking on RunPlatformExperienceHelperOnUnlock and disabling this task made the popup go away.
Just was trying to help as I don't have that issue.