Re: the disposal that runs briefly then shuts down…
You mentioned you had to press the “reset” button to get it to run again (briefly, I presume, before it shut down again).
Would you by any chance be referring to the reset button on a GFI outlet?
If you have the unit plugged into a GFI outlet, it will trigger the GFI breaker in the outlet. GFI outlets are not intended to supply appliances such as refrigerators and garbage disposals that have motors that draw large currents on start up.
I suspect that this is your problem, as I have seen it many times. If that is not your set-up, you have a problem with the disposal motor and need to replace the unit.