garbage disposals are built fairly well... this was yrs ago but the first time mine gave me issue, i had thought that my garbage disposal pooped out on me... it made noise but it wasn't spinning like something was preventing motor from doing so...
however, i called the 1-800 number on the disposal itself and a tech was able to help me diagnose the problem... all i needed was an allen wrench/hex key appropriate for that there center hole on the bottom side of the garbage disposal... he said that i would have to turn it to see if it would spin freely... i tried but it didn't spin and so he told me to use more force... with more force i was able to dislodge whatever it was inside of the disposal free and got it to spin freely... i then went on to turn my disposal on and worked like new...
the second time my disposal went out on me... i called them again... they told me to make sure that my breaker hadn't tripped... which it didn't... they then told me to press the little red button there on the underside to reset the electrical... i did and worked, again like new... 12 plus yrs and i haven't had to replace it... *knock on wood...!