ok, so, new build, no monitor as yet so I have been using the TV through the HDMI port on my GPU (HD7870). the audio through the HDMI stopped working as soon as I had finished installing the supplied audio drivers, ok, wierd, so tried (hot) unplugging and plugging the HDMI cable.
I have had no picture since unplugging that cable. Could this have blown a GPU?
Some times the driver freaks and decideds there is nothing plugged into the hdmi port so it turns it off. I would power down unplug and repluge the hdmi then power back on. If that does not work I would use a vga cable and try again. I would then install the amd drivers from the amd site and not from the CD.
The fact that you lost sound may not mean anything because often the motherboard onboard sound driver is set as default sound device in windows.