How come when I download avi files Windows Media Player won't allow me to play it or if it does play it is only sound and no picture, is there something I can download to fix this problem or what?

Codecs, codecs, codecs. Do a Google search for "Windows Media codecs avi" or something like that. You are bound to find something or other.
Otherwise, get a different player that will play most of the files (google up "VLC" or "mplayer").

__________________
iMac G4 OSX 10.3.9
RAM 256MB
LW 4.10.5 Basic
ADSL anything from 3 to 8Mbps/around 1024kbps

"Raise your can of Beer on high
And seal your fate forever
Our best years have passed us by
The Golden Age Of Leather"
-Blue Öyster Cult-

Search this forum for 'codec(s)' & set it for within the last week & you'll find sufficient links to where to find what you're looking for! This 'will' solve your issue. oatherwise VLC as was suggested!