The HDMI works with the cable box, but there is no audio when I tried to use it with the PC. It is a Acer Aspire X1200. I have seen posts about this problem and updating the bios for this PC. I updated the bios for it a while ago from the Acer website.
The only other speakers that I have connected to the PC are USB monitors. But the audio configuration thing says that there is nothing connected to the HDMI. I tried it without the monitors connected and it didn't help.