What is the best way to convert a .rar video file to DVD video format? I currently use a registered copy of AVS converter software. Will it convert these files to DVD?

It depends on what the decompressed file is. Any file type can be compressed in to a .rar file.

First its not a good idea to piggyback your question on someone else's. This can lead to confusion. You should start a new thread. So I've moved your question to its own thread.

A RAR file is a comprssed version of a different format. You don't convert the RAR file, you decompress it and then convert the decompressed file. So it depends on what that format is.