Turn off power to the disposal before attempting to clear the jam. Use the wrench to turn the blades in both directions to loosen the obstruction. Try to run the disposal again. If you don’t hear the motor at all, it’s possible that your disposal’s overload protector has been tripped. If your disposal has this feature, it can be reset by pushing a button somewhere on the outside of the unit.
After using the lowest cost disposers for over 20 years now, I find the newest models have not withstood regular use for more than 5 years. The older models had a blue housing where this next step-up model has a black housing which I am hoping for at least 5 years use. Our oldest (blue housing) disposers have lasted at least 5 years and some are now almost 20 years old.
Run cold water while the disposal is on. Keep disposer and water running for 30 to 60 seconds AFTER the waste matter has cleared your drain. The waste still has a distance to go. Cold water keeps the motor, bearings and shredder assembly from overheating. It also lets the waste go down easier because the water is pushing it down. Don't use hot water, because it can melt fat and allow it to re-solidify as a blockage further down in the drain.
You should first find out whether only the disposal is broken, or if the power has gone out completely in the areas near your kitchen sink. Try resetting the circuit breaker that leads to the kitchen, or replacing a fuse if you have an older electrical box. If the garbage disposal makes no noises at all when you flip the switch, you might also want to check under the sink to see that it’s plugged in.