FIXED IT !!!!!
Went online and did some research specifically pertaining to 'VISO blank screen'. Appears my issue is realted to 'black light' option on TV.
One recommendations suggested going through the menu options to 'picture' control and turn off the 'black-light' feature. I did that and whal-la picture working fine now......
I think what this black-light function does, is limit the actual white light mixing with other colors on the screen. Not sure what the factory setting is, but ill check that, and may reset TV just to check it out. I suspet all digital TV's have this 'black-light' option, and nothing unique to Visio.
Anyway, the TV seems to be working fine again. Next TV however, will not be a Visio, as I think they're at the bottom end of the scale.
As always , thanks to the Forum for their help to diagnose the issue.
Bigdog