Ok....Submariner problem!

[SubmarinerMan]

Ok guys

Got up this morning and thought I'd go back to wearing my 16610. I got the watch out of it's case and started to wind the watch because it had stopped the day before. 40 turns of the crown...nothing. 50 turns and still the second hand won't budge. (Getting slightly worried)

Then I decided to give the watch a few swirls to see if that will start the movement up. Yet again, nothing. (Very worried)

Finially I decide to shake the watch to see if I can hear anything inside the movement and every time a shake it it sounds like a metallic knocking as well as 'click, click' noise but still the second hand isn't moving at all.

What could this possibly be? The watch is only a 'M' serial and will be 4 years old on the 18th. Also, it was serviced by St.James when it was a year old due to a few problems. But apart from that the watch has been running fine over the last few weeks.

Matt.