Have you oiled your machine? Get out your manual and oil(sewing machine oil) and oil it
If it moves and is not an electric wire oil it. My friends froze up and I oiled it twice and is now purring like a kitten.
Take the bottom off and get the dust bunnies out. Oil, Oil, Oil Make sure your bobbin winder is not stuck 1/2 way...it won't show but messes up your machine. Read your manual ... look for adjustments.... check settings If you don't have a manual look for it on line...Oh, did I say to oil it.