In Unix, Linux and BSD renaming file extensions is easy. In Windows, it can be a bit trickier depending on what you're working with. If you need to rename a file extension in Windows but it won't let you, just get any ftp program (I use Filezilla and FireFTP) and open it up, navigate to the file you want to work with, and rename it. That easy.I had an .img file I needed to rename as .iso to work in Virtualbox and Windows wasn't thrilled about this, so I popped open Filezilla, renamed the file extension, and all is well now.
