Sigh...it seems this should be so simple. I'm trying to replace a wall switch that powers a fixture above a bathroom cabinet. The box has only two wires, one black, one white. When using one of those current testers, only the black beeps red. Back wiring was used on the old switch (stupid, but I can't remember which wire, black or white, was on the bottom). The old switch did not have a grounding screw, and I do not have a grounding wire in the box. The new switch does have a green grounding screw, which I of course ignored. I don't know if you can still buy them without. I did the back slip connection, hot on the bottom, and successfully got current to the light fixture. My question: when I use the current tester and touch the metal framework of the switch, as well as the side screws that I'm not using, it turns red and beeps. I assume there should NOT be current in the metal framework, and wonder if I've done something wrong, or should buy a different switch. As I mentioned, it seems identical to the old except for the grounding screw. All suggestions welcome. I can't see paying an electrician for such a small item.