I have a HTPC built around the Acer Revo R3610 and Windows 7 Media Center (Service Pack 1 installed). This is connected to an LG 42LK450U TV via HDMI (direct, no AVR). When I first set it up, I would often find that there would be no audio in Media center after resuming from standby. I appear to have resolved (or at least worked around) this by setting Media Center's ehshell to close and reopen on resume. This seems to work most of the time, but this evening the HDMI audio simply stopped working whilst the system was up and running. As with resuming from standby, closing and reopening ehshell brought the audio back. Any ideas why this is happening? Why is HDMI so problematic?