Avi

how do i down load a dvd to my computer ive been told i have to change it to avi .what does that mean and how do i do it:confused:

I assume you refer to backing up your DVD to a movie file on your PC, also referred to as ripping.

In this case I would suggest reading this tutorial:
http://club.cdfreaks.com/showthread.php?threadid=59485
In that forum there are several other tutorials that might be of interest.