.RAR conversion help

[Basillex]

Does anyone know anything about RAR conversion? I am using Windows Media Encoder to compress videos we get in here at work into an .wmv format. I have never worked with .rar files before and it is frustrating. Here are the steps I have taken so far:

I have received some files with an .rar extention and used 7Zip software to unzip the files. After it unzips them, it shows them as .avi files. But when I try to convert them in Media Encoder, I get this error message:
"The input media format is invalid" I have converted .avi files in the past, so I am guessing that although they now have that file extention, they are still .rar files. Does any one have any suggestions?

[MilesAhead]

Is this a sequence of .avi files that have to be assembled or is it just a couple of .avi files?
If the files are broken up, after joining you may have to rebuild the index. Try loading the .avi into AviDemux. Make sure Edit=>Preferences=>Automation Tab has all the options checked. It should automatically fix the index if needed when it loads the .avi. Then just save.