Connect PC to HDTV via HDMI. Sound at HDTV but not through AVR surround speakers. HDTV to AVR via optical connector (Toslink). What can I do differently? The movie (s) are HD and Blu Ray .
normally i would suggest PC->AVR via hdmi and AVR->TV via hdmi.
however, if you have one of those cheap htib units which does not have hdmi inputs then you might be forced to run PC->TV via hdmi and PC->AVR via optical. you would need to then select optical as your default audio device or sound will pass through hdmi to your tv instead.