this is more of a computer question than an electronic one ...
very simplified answers without running to google ...
.avi is divx or xvid.
mov is quicktime.
'media player classic' is a good player for avi.
videolan i believe is the name of another commonly used one.
both are free.
you can of course also use windows media player, but I avoid it.
For mov's, you can use quick time ... or i believe there is a prog called 'quicktime alternative' (similar to 'real alternative').
you *may* need codecs to play back the videos .. but don't randomly install them unless you do. If you do, google for klite codec pack.
if you get something that you can't play back, there's a program called 'gspot' that will tell you what codecs were used in encoding a video, so you know what you need.
hope this at least gets you started in the right direction
also moving to computer forum ...