My GE Microwave sounds like its on, however the carousel stopped turning and nothing is getting hot. This is a GE Combination in wall oven and microwave unit.

Well if you can get it opened, that get to the inside, you could look for a blown fuse. Be very careful you can get shocked even if it is unplugged.
Other than replacing a blown fuse there is nothing you can do .
Call a repairman.