Hello Nadine,
Check the plug to the machine and check the pins on the socket on the machine, unlikely the foot control will just pack up completely unless you can hear the carbons rattling about when you shake it if they have broken, there ios a way of checking whether it is the foot control or something else and that is by taking the foot control off, take a short length of cable with a light socket on the end, put a bulb in the socket, connect up the wires of the foot control lead to the light lead and switch the machine on and it should run slowly, if it runs then you need as new control, if it does not then you may either have a break in the wire to the machine or inside the plug on the machine.
Ken
drivewithken
June 2010