Ableton Forum

I was making a track in Ableton and a few days ago i started up ableton how i normally do and for some reason every time i press a note to play any kind of instrument, instead of playing one continuous note it starts stacking and i get this disgusting sounding jumble of notes the same tone but very sloppy

help please?

also, i have no special equipment i just have my keyboard and whatever came with Ableton