  We study the production of $c \bar{c}$ pairs and dimuons from hard collisions
in nuclear reactions within the covariant transport approach HSD. Adopting 6 mb
for the $c \bar{c}$-baryon cross section the data on $J/\Psi$ suppression in p
+ A reactions are reproduced in line with calculations based on the Glauber
model. Furthermore, using $J/\Psi$ absorption cross sections with mesons above
the $D\bar{D}$ threshold in the order of 1.5 - 3 mb we find that all data on
$J/\Psi$ suppression from NA38/NA50 can be described without assuming the
formation of a quark-gluon plasma. Alternatively, we also investigate an
'early'-comover absorption scenario where the $c \bar{c}$ pairs are dissociated
in the color electric fields of neighboring strings. Again we find good
agreement with the experimental data with an estimate for the string radius of
$R_s \approx 0.2-0.25 fm$.
