Are you sure you didnt "lock" the voltage. Try pressing both + and - at the same time for a few seconds.
Wow, you are right, that worked. Somehow I must have accidently locked it. Glad to see that all was not lost, like I thought. Sure glad I mentioned it here, otherwise I probably would have gone on being annoyed oblivious to the fact that it could be fixed. Thank you so much. It really is great to get answers for questions like this.