avi files on usb into tv?
first look at your manual or go online to your product site, ie panasonic viera lcd tv. it should tell you what format it will read. i have one and it reads Mp4 and MKV. Use "micro video converter" or any converter that converts from avi to mp4 or mkv (or whatever format you lcd will accept). then copy to your usb and plug into your usb port on your tv. it will work.
(by the way there are many free converters online, be sure you get one that is free not a free trial, because they will only convert a few minutes of it or will have a water mark on it while playing your movie.)
on your pc the software "vlc" works great..it plays most file formats.
hope this helps.