That's not exactly going to work.
Like every lossless compressor, WinRAR only works once on a given file - repeatedly compressing it can and will actually make the file swell in size, so after two RARs you've already got a reverse effect. Same goes with any other compressors and combining them (ZIP to TGZ to RAR to ACE to 7ZIP to BZ2 to...)
As for the MV2 file... apparently it's a regular MPEG-2 file - try renaming it to <filename>.mpg and see if it will open normally under your default video player. Of course, you have to have the option of editing the extension enabled (under Folder Options).