I edited a movie and now want to render as but when I save as an AVI or MOV file, and try to play the video file back afterwards, there is no video or audio, just a blank screen with no sounds.  There a million formats to choose from and I'm not sure what I should use.  I always used AVI or MOV format in the past.  I have a converter package that I used to take the AVI file and then convert that into m4v, wmv and mov files.  I want it to be as high resolution as possible.  Help please!