Press Ctrl + Shift + Esc to open Task Manager
Find the app under the Processes tab
Select the app
Click End task
Press Alt + F4 to close the active window
If the app is frozen, use Ctrl + Alt + Delete and open Task Manager
Right-click the app in Task Manager and select End task
Open Command Prompt as administrator
Run taskkill /f /im appname.exe
Use PowerShell as administrator
Run Stop-Process -Name appname -Force
Restart Windows if the app still will not close