mouse is not turning on at all but the red sensor is kinda on

mouse is not turning on at all but the red sensor is kinda on mouse is not turning on AT ALL ( no lights or life in it , not showing on computer ) EXCEPT for the red sensor on the bottom is on with a very VERY dim light and it responds to the movement ( gets a bit brighter when scrolled over by my finger ), and stays on even when the mouse is switched OFF!!