We study the blowing-up of the four-dimensional Z_3 orientifold of
Angelantonj, Bianchi, Pradisi, Sagnotti and Stanev (ABPSS) by giving nonzero
vacuum expectation values (VEV's) to the twisted sector moduli blowing-up
modes. The blowing-up procedure induces a Fayet-Iliopoulos (FI) term for the
``anomalous'' U(1), whose magnitude depends linearly on the VEV's of the
blowing-up modes. To preserve the N=1 supersymmetry, non-Abelian matter fields
are forced to acquire nonzero VEV's, thus breaking (some of) the non-Abelian
gauge structure and decoupling some of the matter fields. We determine the form
of the FI term, construct explicit examples of (non-Abelian) D and F flat
directions, and determine the surviving gauge groups of the restabilized vacua.
We also determine the mass spectra, for which the restabilization reduces the
number of families.Comment: 19 pages, Late