Hello,
You cannot convert a .rar file to a .iso. It uses different compression. Sounds like you downloaded an iso in rar format and are stuck on what to do with it. You will first have to extract the contents from the rar and then depending on the format of content, you will chose how to convert. Most likely the .iso is inside the .rar. The .B00, .B01 and so on are just one huge file/content split into smaller parts. Either start with the first one, .B00 or a .rar and open wit with WinRAR, click extract and you should have your iso content.
