RealPlayer plays mp3 files too. If what you want to know how to have something other to open your mp3 files it is easy. Depends what program. Yes, sometimes those preferences get changed. Most of the time go to the preferences of the program you want to open your mp3's. iTunes you open itunes and open preferences. Find the setting to use for internet playback. Check it your done. Check it out, need more help, os and program you wish to open them would help.