Press Windows key + Ctrl + Shift + B to reset the graphics driver
Press Ctrl + Alt + Delete and choose Lock
Press Windows key + L to lock the screen
Open Task Manager with Ctrl + Shift + Esc and end the unresponsive app
Press Alt + F4 to close the active window
Use the built-in screen freeze or presentation mode in your software if available
Press the power button briefly to sleep the computer if configured
Use a remote management tool to pause or lock the session if needed