Troubleshooting an InSinkErator garbage disposal machine usually involves identifying if any loose objects are locking the disposal up, checking to see if the overload protector button has been tripped or if there is an issue with lack of power. InSinkErator.com has more troubleshooting information.
If the InSinkErator is jammed, try inserting the end of a sturdy wooden stick or rod into the mouth of the disposer to manually rotate its base and free any lodged materials. You may need to use some force. Once the base turns freely in both directions, locate the red overload protector button on the underside of the disposer, and press it. If it won't stay pressed, try again after a few minutes.
Another way to work on a jammed InSinkErator is to insert the self-service wrench included with the disposer into the hole at the bottom of the disposer. Work it backward and forward until the disposer turns freely.
For both methods, you should disconnect the power from the disposal system first. Make sure there are no rigid, nondisposable objects in the disposal chamber. When the troubleshooting is complete, reconnect the power, run the cold water, and turn the disposal system on to test its function.