Is a two stage type with an auger and a high speed impeller that blows the snow.
IF the high speed impeller turns and the auger doesn't, chances are the shear pins that drive the auger are sheared and you need new ones. (easy fix) The shear pins are about $1 each and you can get them from your local dealer.
If neither turns, then chances are the spring loaded dog clutch that drives the high speed shaft is either hung up or broken. (not so easy of a fix)