With the PC directly connected to the HDTV, try booting into safe more to see if you get an image. Make sure the PC is set to display the native resolution of the HDTV.
Yes I have given this a go and still to joy. Interestingly enough I have loaded up Linux on this PC and low and behold no HDMI issues. This is definetly a Windows 7 thing.
I have read of other people with HDMI issues over Windows but have not seen a fix.