I guess the easiest answer is that of organisation and intetion. You can make music banging two rocks together if you do it in some more of organise way and the intention of music rather than just random banging. I'm sure people have made "body music" before...doing nothing but slapping their skin, clicking their joints, etc. And of course things like beat-boxing are an extention of that...when it comes from being random sounds to as they say "making music with their mouth." I certainly wouldn't have a problem with anyone saying things like bird and whale song are some form of music.
That of course means it's very hard to stop music from being music and make it noise. Now, while loud angry stuff seems to scare half the people here and as much as they dont want it to be, it's still music. You have to turn the distortion all the way up til it's near pure white noise really. People are still playing instruments and they could be playing any well know pop song, just really loud, really fast and with loads of effects, still music.
When it does finally reach just beating your instruments around Injected Bleach style, that is noise. Doing it as part of a song, as section, experiemention is just music...but truely random smashing your guitar around crosses the line maybe.
So, most noise is music and it's really hard fro music to be "just noise" whatever people want to think...in my view.