Why does my L120 fail to turn on and off?

Why does my L120 fail to turn on and off?

With several sets of new AA alkaline batteries, my Nikon Coolpix L120 camera intermittently will not power on or off. I suspect battery contacts, but even after cleaning with rubbing alcohol and ensuring adequate pressure/spring, I still have this problem. It seems as if a firmer press of the on/off switch helps, but not always.