  We scan the complete parameter space of the supersymmetric standard model
extended by a gauge singlet, which is compatible with the following
constraints: universal soft supersymmetry breaking terms at the GUT scale,
finite running Yukawa couplings up to the GUT scale and present experimental
bounds on all sparticles, Higgs scalar and top quark. The full radiative
corrections to the Higgs potential due to the top/stop sector are included. We
find a lower limit on the gluino mass of 160 GeV, upper limits on the lightest
neutral scalar Higgs mass dependent on $m_{top}$ and the size of the soft
supersymmetry breaking terms, and the possibility of a Higgs scalar as light as
10 GeV, but with reduced couplings to the Z boson.
