I know it will sound silly but... Are your feed dogs up? :wink:
How do I know this? Yep. Tried and tried to sew and nothing would work. Dumb machine! Ha! More like "Dump operator!" Once the feed dogs were raised it worked a charm!!! :oops: Didn't have to go to the repair shop at all. Thank goodness I figured it out before it cost me a service fee!!!!