I have a Black & Decker 12V electric screwdriver. The mechanism that holds the screw bit in has locked at it's fullest extent.

This happened when I was unscrewing a screw and didn't tighten it up enough. When I pulled the trigger, it span around and locked up.

I've sprayed it with WD40 and trying as hard as I can, I can't loosen it.

Nick Wright, May 2010