Are you getting any power at all? Is the light coming on?
I just had the problem with my Juki 2010Q. The light came on, but nothing happened when I pushed down on the foot pedal. I tried a number of things with no luck. Finally broke down and drove the 45 minutes to the dealer to have him look at it. Then came my "duh" moment - when I had filled a new bobbin, I left the shaft that goes up against the bobbin as it winds in the neutral position - neither all the way in or out. Apparently, the machine will not sew unless the bobbin shaft is fully extended. What a waste of time and gas. Could have been sewing for that hour and a half.
If you are not getting any power at all, try spreading the prongs on the plug open a little more. Sometimes they get squeezed and don't make the proper contact in the socket.