Honda 724 snowblower won't move forward or reverse. What could the problem be?

Hi,
Well, to begin there are four models, all roughly the same. First guess would be the drive belt that goes to the transmission. Her is a link to the page that lists Honda snowthrowers at one parts dealer. Pick a 724 and check the page for Pulley - driven making sure to pick the drive not auger pieces.
All Years Honda Snowblower Parts
Peace,
Clarke