My Sub has gone mad

[misterhyde]

My Submariner 16613 has gone berserk, but seriously.It's going so fast that I think its going to take off!
Well maybe this is a slight exaggeration, however 15 seconds a minute or 15 minutes an hour means something is seriously wrong.
I might have knocked it this afternoon, but nothing that I've not done before.
What do you think has occured?

My apologies if this subject has already been covered or if I've posted it in the wrong sub forum.