How do I unlock my cordless B&D drill?

I already found the answer here from 11 months ago, but it's not working. I twist the sleeve to the pic of the drill, I put the drill in reverse, I hold the end of the drill and press the trigger. Nothing. I've used this drill many times and its never locked on me. It WONT budge. All I wanna do is stick a bit in and drill some holes, but it won't unlock :( Please help me. I've been trying for 24 hours off and on.