Phillips Plasma (42") no picture (almost)?

Our ~2 year old Phillips Plasma was on today & the picture went away but the sound stayed. THe screen is black except that there will be flashes on parts of the screen, mostly a red tone, at seemingly random intervals. The flashes are not consistent for size or location and may be more frequent when we try the remote but no definite correlation.

I have unplugged the TV and let it sit (~1/2 hour) with no change. I have cycled it on/off a number of times. Each time the green light comes on or goes off appropriately & the sound is always there. We verified incoming signal to the house on other TVs (one a Phillips LCD of similar vintage) & tried a different video source, DVD & VCR. Still no picture but there is sound & it will change volume, mute, etc. I have also pushed every button on the remtoe & TV itself hoping that something had been pressed that toggled a setting.

Any help? We like a picture with our sound.

Thanks