How to pop a SYSTEM shell on the Windows login screen using sticky keys
Pressing Shift 5 times triggers C:\Windows\System32\sethc.exe. On unencrypted Windows systems, replacing that with cmd.exe will let you get a shell running as SYSTEM from the login screen.
How to pop a SYSTEM shell on the Windows login screen using Utilman
Utilman.exe is the built-in Windows app to provide Ease of Access options from the lock screen. It’s launched by clicking on the Ease of Access button.