Hello. My 22" widescreen monitor was previously using the VGA port on my HP PC. I added another older flatscreen (15" square) to the setup. The older monitor now uses the VGA port, and the 22" uses the HDMI port. With the PC using the HDMI port, I cannot hear any sound from the speakers built into the 22" screen. You can see that the sound is coming in, but I cannot hear it. What's up?