I built a Video Arcade cabinet a number of years ago and recently upgraded the video card and monitor.
The video card has outputs: SVGA, HDMI, and DVI. The monitor is a 28" TV/Monitor with Component Input, SVGA, and HDMI. I originally hooked it up with SVGA because I had a cord available. Worked great. I've always heard that HDMI is better, so I picked up a new HDMI cord (didn't have a spare).
Plugged it in and changed the TV/Monitor input settings. Video works, but I lost sound(?)
Didn't make any sense to me, so I plugged the SVGA back in and it works fine and sound.
Unplugged the SVGA again and plugged the HDMI back in, no sound.
Unplugged the HDMI, so nothing plugged into the monitor and I have sound again.
The HDMI is definitely cutting off the sound.

Am I missing something obvious?? Just recurred to me, could the sound be routing to the TV speakers? (I had the TV speakers turned completely down. If so, how do I revert it back to my PC Speakers (tV setting??))