ableton going crazy

[dt]

this problem has just started. everything runs fine, then all of a sudden the track goes crazy, all the sounds sound timestretched, the tempo is all over the place, its just total noise. the cpu runs the same as before. sometimes when i start again it runs for a while then starts after a while. other times it runs all day fine. any ideas or has anyone experienced this before? thanks in advance

[dt]

another thing i noticed, is that the play marker scrolls across the arrange view very fast maybe from 0-the 30 second mark in 5 seconds. and the orange triangle index marker, scrolls along the arrangement view by itself, when the project has been stopped.