  Notes of three talks given at the workshop 'Hilbert schemes, non-commutative
algebra and the McKay correspondence' CIRM-Luminy (France) October 2003. If A
is an order over a central normal affine variety X having a stability structure
such that the variety of all semi-stable A-representations is a smooth variety,
then the corresponding moduli space is a partial desingularization of X and we
have a complete classification of the remaining singularities.
