Hi Ellie,
A couple of things worth looking at.
Ok,.. the stop motion "washer", under that big knob, should have the flared part, the inside "teeth" sticking toward the wheel side.
In theory, I guess the washer being out of place could cause problems with turning the wheel, but I suspect that the problem lies under the bobbin case.
When I got my latest FW, it had a similar problem. The needle would move a little, the hand wheel would turn about an inch either way, but that was it. I had what was close to 10ft of thread caught behind the bobbin case. I could see some of it without dis-assembly, but when I got it apart it was staggering!
This is a write up done by someone else that should show you how to clear it. The threads can be difficult to see, so look very carefully. It's also a great opportunity to dust in there.
http://thefeatherweight221factory.co...MachineJam.php
Good luck! Let us know if it works, or you have further questions.