Press Ctrl + Shift + Esc to open Task Manager.
Find Windows Explorer, right-click it, and choose Restart.
Test Search (Windows key + S) and Settings (Windows key + I).
A Surface force restart also helps- hold the power button for 20 seconds until the logo appears, release, then power on again.
Open Command Prompt as Admin and run these commands:
sfc /scannow
DISM /Online /Cleanup-Image /RestoreHealth
Create a new local user account (netplwiz from the Run box, or Computer Management) and test whether Search and Settings work there. If they do, your profile is damaged and you can move your files across.