Hello Carolyn.
First of all make sure the take lever is at the top and the needle bar all the way up, move the clip that holds the bobbin case to the right, you may have to lift it slightly, put the holder back in, wiggle it about a bit to fit it, push the clip back until it snaps in, look at the gap between the holder and the clip, there should be no more room than a thread width, if the gap is too wide undo the screw and move it closer.
ken, January 2011
