Ran channel scan. Why didn't I find any channels?

get a better antenna or aim your antenna in a different way,you wont get all available channels unless you have an antenna that can turn 360 degrees

Check and replace its main system control memory IC, and re-program it with initial data. If you wish to get some details; check the site linked here. Viewing it in "Mosaic" will make surf easy. Surf the site with patience.
http://electronicshelponline.blogspot.com/ Pull up older posts there.

You can do it manaly.

I think you mean perform the channel scan function. Every tv manufacturer has different wording in the menu, but basically this is what you would do:
Press Menu, then go to Setup or Installation menu (wording depending upon mfg).
Select antenna or cable (wording could be air or cable)
Perform channel scan

Hope this helps as you didn't mention model.

I ran the Auto Scan. Before the scan reached 91%, I pressed the Menu button on my remote and all of the channels that it found locked in.

do u have cable or of the air?

Try bypassing your amplifier. I was getting an incomplete scan, and that solved the problem. I ran the scan without the amp in the line, then turned off the TV and converter and reconnected the amp.