How do you fix a dish washer. it won't do an thing? power is on.?

HOW OLD IS IT. PROBABLY A BAD DOOR SWITCH. DON'T FORGET YOU SHOULD HAVE A SWITCH ON THE WALL THAT NEVER GET USED AND THEREFORE GETS FORGOTTEN UNTIL YOU HAVE A VISITOR OR MOMMY'S HELPER WHO SNAPS IT OFF WHEN SHE MEANT TO TURN ON THE DISPOSER?How do you fix a dish washer. it won't do an thing? power is on.?
verify the power is on, then you have to work backward and eliminate each possible problem starting with the latch switch , it all depends on how old it is it may have anywhere from 0 to 30 kill switches built in for safety, like if it dosen't have any water, the drain is plugged ect.if its not too simple though you need to eaither call a repair man or get a new one.