I also have a Sony LCD TV.
The problem which I experiance is a follow.
This happened 3 times so far from December.
When I switch the TV on to watch TV I also got a black screen.
2* this happened ,I hear sound but no picture with default Dual-View decoder on AV connection.
1* this happened with HD-PVR this week no sound or picture via HDMI.
To solve problem, unplug 220V supply and plug supply back on.
This works every time for me.
I phoned Sony in this regard, they will do firmware upgrade for me.
Not done yet.