Toshiba 32" TV acting up

Hi: I have a Toshiba 32AF42 that is working strangely. Occassionaly, any station on the highband channels (6-11) look like they are getting corrupted by electrical noise (enough so the picture is almost blurred out) or, sometime the picture looks like the tuner cant quite lock on to the signal (actually the picture reminds me of how older TVs displays looked when the AGC was greatly overdriven. In the 'cant lock on to signal mode,' there is a noticeable hum bar that moves up the screen at about 8-10 Hz. There is nothing in the house that is producing electrical noise or a RF interference. Any clues as to what may be dying in the set? Also, is there a way to reset the processor on the board? Perhaps this might help. Other suggestions appreciated. Thanks John