Try switching to external monitor. On my new Dell laptop it's F1 to switch. On my old laptop it was Function key + F8. Check your manual for your hot key or look it up in Help. HDMI to a monitor will only have the video, no audio.
For the HDMI output port to work, do I need to activate it in some manner? I appear to be getting no signal output from this port and don't know if it is defective or just needs to be activated by some procedure I don't understand how to do.