If the disposal is plugged in and doesn’t need to be reset, then you should check the circuit breaker. The breaker could be flipped, which would mean your disposal isn’t getting power. If that’s still not the problem, then either the outlet is dead, the circuit breaker is malfunctioning, or the disposal needs to be replaced. Check the outlet first by plugging something else into it. If the outlet works, try replacing the circuit breaker switch. If that isn’t it either, you have to replace the disposal.
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.