Is there only 1 cable entering the switch? If so, it's a switch leg.
If this is the case, Power comes into the switch on the white, and returns to the light on the black. Connect the ground wire to the box, and use a single pole switch. The switch will have 2 brass colored terminals. White wire on one and black wire on the other. Ground wire goes to the green screw if the switch has one.
Edit: individual above me beat me to it and included a diagram.
If this is the case, Power comes into the switch on the white, and returns to the light on the black. Connect the ground wire to the box, and use a single pole switch. The switch will have 2 brass colored terminals. White wire on one and black wire on the other. Ground wire goes to the green screw if the switch has one.
Edit: individual above me beat me to it and included a diagram.
