Before calling the dealer, make sure that you are threading the machine correctly, even if you've been doing it for years. Get the manual out and double check. Make especially sure that when you thread it, the presser foot is up so that the thread goes thru the tension disks. Put the foot down when you thread the needle. Then, with the foot down, gently pull the thread from the needle towards the back of the machine. There should be tension on the thread. Sew a sample. If this doesn't work, then I agree with everyone to call the dealer.