Black screen on digital channel on my vizio

I was getting a beautiful digital picture on my 47" Vizio Gallevia with a straight cable to TV connection (No Box) . I rescanned after the transition in an attempt to get the few channels I was missing and lost all digital channels. I get a black screen with the channel listed on the screen but no sound or picture. I only get the old standard channels now. It appears that when I rescan now it skips scanning for digital. I wish I had left well enough alone. Can anyone PLEASE help me!