You can play avis with programs such as mplayer. You're in Fedora, so odds are, you're using the rpm package management system. Type rpm -q mplayer to see if it's installed. If it is, type mplayer & to run it. If it's not, you will need to download it from one of the many RedHat / Fedora mirror sites.
to install programs in fedora use the yum function
type su then your root password
type yum install (program)
mplayer is not a recognized program in GNOME so make sure the program you are wanting to use is in the right enviroment
In Ubuntu I use Totem movie player that come by default. I just click a any .avi file and the OS search for the file libraries and just add to the player. I am sure it is similar to Fedora. Shouldn't be difficult.
trickier with fedora as redhat ( a us registered company) are paranoid about patent infringement so cripple its multimedia capabilities. Cant get codecs from the official repos.
Try several Distro and see which one work best for you and stick to that. Thats how I settled with Ubuntu and its work great on my 7 years old notebook. Take a look at this website http://ubuntuforums.org for more info.