HP Laptop HDMI Signal Failure

To confirm the symptom of a missing HDMI signal, connect the laptop to an external monitor known to be functional. Verify the absence of signal by checking if the monitor remains in a power-save mode or displays a 'No Signal' message despite the laptop being powered on. Use the Windows key + P shortcut to toggle between display modes (Duplicate, Extend, Second screen only) and observe if the operating system acknowledges the presence of an external display in the Display Settings menu.