I should have added above that I updated the one available Samsung firmware upgrade back in February well before this problem arose.
I have downloaded it again but will install it again when all else fails I think.
The TV is a Samsung 50" Plasma PS50 B650 S1 FXXY.
Three months out of Warranty!
I am only able to access one of my four HDMI inputs.( #3 )
If I connect ( plug in )another input signal to any other HDMI port the signal of what is showing on HDMI 3 is replicated there. Have tried different devices. Have quality leads.
Only using two inputs. 1. Tivo ( incl live TV ) and 2. WD HD LIVE. Have been working without fault for two months.