  If the lightest chargino is discovered at LEP2, the measurement of its mass
and cross section together with the mass of the lightest neutralino, enables
the determination of the parameters that define the theory and the entire
supersymmetric and Higgs spectrum. Within this context, we: (i) study the
effect of the one--loop tadpoles in the minimization condition of the Higgs
potential, by comparing the RGE--improved Higgs potential approximation with
the calculation of the minimum including the effect of the one--loop tadpoles,
and (ii) compare the prediction of two different supergravity models, namely,
the model based on $B=2m_0$ and motivated by the solution of the
$\mu$--problem, and the minimal supergravity model, based on $A=B+m_0$.
