First, you do not need a DVD-ROM to view an .avi file...
I am assuming that you are running a Windows Operating System-
If so, try installing a 'pack of CODECS'...
Click on the following link to see another post on installing Nimo Codecs...
http://www.gnutellaforums.com/showth...highlight=nimo
If that doesn't solve the problem(s), it may be that the file you are trying to view has some 'problems'.