96 ram is a problem that you have. higher the ram the better.

Anyway use realplayer. I have an older version of realplayer and all they will do is add files and update realplayer so you will not need to pay anything.

Avi's are notoriously played by Realplayer
also RM is very popular in Realplayer.

http://www.real.com/player/?src=realplayer is where you may download a free version, you may also go to www.serialz.to and get serials etc.. for realplayer to you may have more than a 14 day trial.