42'' Magnavox 42MF231D/17 with picture/sound problem

I have a 42'' Magnavox Plasma 42MF231D/17 that is about to turn 3 years old. Just the other day, when the TV was turned on, it shows a weird color ''pattern'' or ''snow'' and turns red after a couple of minutes. There is also no sound. The power cable was removed for over a day to try to ''reset'' the unit with no luck. All cables have been checked and even with no cables attached (other than power cable) the same problem continues. Any Ideas??