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.
Watch the video below for tips on fixing your garbage disposal unit, including instructions for how to take it apart. If your unit still won't work, then you probably have a burned out motor or an electrical problem, which requires the expertise of a professional. This is when you'll want to call a plumber to replace your garbage disposal unit. It's a fairly difficult DIY project to replace your garbage disposal unit, but if you're up to it, here is a DIY guide for garbage disposal replacement.
Another common cause for a leaking garbage disposal is the disposal flange. A leak at the very most upper area of the garbage disposal could be the garbage disposal flange which goes through the sink. A garbage disposal flange should be sealed with Plumber’s putty and then tightened from underneath the sink. If this is not tight enough or if it has managed to come loose (which can happen) then the garbage disposal will have to be taken down so the flange can be resealed and then the garbage disposal can be rehung.