help with file extension

Hi
I just download multi-files and they turnt out to have RSD file extension in the end. my pc cant read it. what do i need to install please?
Answer #1
The .RSD file format is used by Roland's Visual MT music Tutor application.
Answer #2
http://extensions.pndesign.cz/rsd-file
http://www.econsultant.com/file-extensions-r/rsd-file-extension-roland-visual-mt-file.html
Answer #3
thanks but these are just defenitions guys!! i need a clue please.