https://www.google.com/search?client...w=1192&bih=567
maybe you can find answers at this troubleshooting page. I experienced a similar problem last week and I felt so stupid. Had not used for a while and I set my desired stitch, turned on machine, light and found the machine would not sew. Panic! Started investigation and discovered I had forgotten to turn on the box itself..the button was on the end, hidden away and my memory had failed!
I hoipe your 'fix' is as simple as mine. But, sorry, I have no other suggestions.