When it's in the black-screen state, can you log in remotely and see what it thinks its desktop topology is? and the EDID of the HDMI output? I bet it's put itself in a non-square-pixel mode. The graphics driver can probably enter such modes, and the screen can probably scan them, but GDI will rightly refuse to go anywhere near them.

If so then perhaps the receiver is failing, or partially failing, to read the EDID and is returning a default or corrupt one. If you have another HDMI cable, try swapping out the receiver-to-TV one.

Peter