My machine wont sew

If the top thread is not pulling up the bobbin thread, is it actually catching the bobbin thread? If not, then the machine may be out of time. Search for sewing machine timing or take it for service.

If it catches the bobbin thread but then the bobbin thread is difficult to pull, then possibly there is a snag somewhere that is catching the bobbin thread, the bobbin tension needs adjustment, or the bobbin case is incorrectly threaded.

Most of the time that means that the timing of the machine has become off for some reason. The timing is when the needle catches the bobbin thread. If that is not right it won't catch the bobbin no matter what stitch you try. Unfortunately there are about7 different adjustments that it could be that will fix it. You can try talking to the people at the link that I attached or you may have to bring it in to have someone professionally adjust the timing. Good luck. Sewing Machine Repair Repair Sewing Machines Sewing Machines Repair Fix...

Take a look at these 4 images (Click each one to Zoom)
Sewing Machine Hook Timing
Very good chance your Timing is slightly out, often after a jam or sewing heavy fabrics...
Not an easy home fix without a Workshop Manual

try changing the needle
also try rethreading the machine top and bobbin
make sure the bobbin is turned the correct way in the bobbin case
if the suggestions don't help then it's possible that the machine
needs to be checked for a timing problem

It loops, it's just that your shuttle isn't catching the loop. The loop is formed on the upstroke of the needle on the back or "scarfed" side of the needle. If the shuttle point doesn't catch that loop, no stitch.

First make sure you have a fresh needle. If still no stitch... take it in for service. (clean, lube and time)

try changing the needle
rethread the machine top & bobbin
if these suggestions don't work I suggest taking the machine to a
sewing machine shop to be checked

To learn how to solve the bobbin catching problems and select the correct needle, I suggest you to order the following product:
Sewing Machine Repair Guide
It's a professional step-by-step repair guide written by an expert. Besides Singer sewing machine, you can learn how to repair other brands of sewing machine as well. The author claims that you can earn money after you had learned the repair skills!
Good luck.

On mine this means the button for reverse is stuck. Just wiggle the button a bit and it will pop out again. It can get pushed in at a slight angle and catch a bit, but nothing is broken... I don't know if this is the only thing F2 means, but it is one thing!

Try flipping the bobbin. The thread must come off in a certain direction to work properly.

Your machine is out of time. It would be best to have a tech adjust the timing.