Does the light come on when you plug it in? Are you getting any juice at all? Does the motor try to move or make any sound? Do the wires look okay visually? (No frayed, cut, or joined areas) When you flex the wires, do you hear any cracking sounds? If you turn the hand wheel, does it move freely or do you really have to crank on it to get things to move?
It could be a lot of things - might be a bad pedal, might be a wiring problem, might be something jammed up in the machine itself... I think it's best if you can diagnose where the problem is before you take it in, particularly if you don't know/trust the repair person yet. But if you're not sure where to even start, a repair person or your nearest sewing machine geek is probably where to go next.
Worst case scenario and your motor is shot - you can buy new replacement motors online or you can try for one on eBay. I actually recently bought a motor & light assembly for a 99K from eBay and it worked great.
I am very fond of 99's - yours sounds lovely!