Magnavox TV Works Fine For 5 Minutes Then Picture Goes Black While Sound Remains

I have a Magnavox 26MF605W/32MF605W series LCD TV that I bought in 2006. It's a TV that I had rarely used so I didn't notice any problems with it really until I had it too long to return to the store because of this issue I have. When I turn on the TV... It works fine... good picture, good sound. But after say, 5 or 10 minutes of playing the TV... the screen goes black, but the sound remains perfect. It's my hope that I can fix this issue myself.

I Thank Everyone In Advance For Any Insight As To What The Problem Might Be.....