Boy are people just getting so lazy they think you can push a button and your work is done! Computers are amazing but how on earth would that even be remotely possible! Do you understand what an audio file is?
Do you think there's a little band in there playing live? That's just about as far fetched.
Yes you can remove vocals, sometimes.
If what your after is a backing track for playing live or making your own recordings, then you have many choices and most either involve spending money or spending time. No magic "free" button to creating backing tracks.
Best shot is there are some free midi files for most popular songs but that is limited and many are not that good.
Google your song title midi file. Be aware of many Phishing sites as you go. Midi files should download fast and direct without jumping through any hoops or installing software.
Example:
http://www.midiworld.com/search/?q=dancing+in+the+dark