Tear it down and see what the damage is. Could be repairable, could be
scrap, but you won't know untill you take it apart. If it is frozen
because it sat for a *long* time, it is probably rings stuck in the
cylinders. You'd replace the rings and hone the cylinders usually (if
the damage was not too bad.) and replace the bearings (as you have it
apart) seals and gaskets.

Look in MV magazine for engines. There are some available.