Is it on the side of the screen (if you slide to open, it shows several apps?)...if so, just press and hold the back key or you can go into system settings, display (I believe) and disable "multi-window"...
Is it on the side of the screen (if you slide to open, it shows several apps?)...if so, just press and hold the back key or you can go into system settings, display (I believe) and disable "multi-window"...