:h
Hmm.. I wonder where the OP of this thread went too...
OP did leave out some info like are you using AT HOME:
Over the air antenna?
Cable?
Satellite?
If you are using cable at home, you must change the TV settings to AIR from CABLE.
If using Satellite connected via A/V patch cords you may have never set the tuner option and it may be set to CABLE..
The reason the tuner must be set to AIR is because cable and over the air broadcasts use a different channel scheme with only a few channel frequencies overlapping not to mention cable uses QAM encoding not ATSC for digital channels..