  A study of the temperature (T) and density (n_s) dependence of conductivity
\sigma(n_s,T) of a highly disordered, two-dimensional (2D) electron system in
Si demonstrates scaling behavior consistent with the existence of a
metal-insulator transition (MIT). The same critical exponents are found when
the Coulomb interaction is screened by the metallic gate and when it is
unscreened or long range. The results strongly suggest the existence of a
disorder-dominated 2D MIT, which is not directly affected by the range of the
Coulomb interactions.
