I posted the problem before, but I got no answers that helped me out.
This is what's going on : as admin I cannot open the SPS
Administration any more. As coordinator I cannot change the security
roles any more. Since today there are no email notifications sent
anymore. Farquat said to check out if the netbios was ok, it is, and
if I hadn't changed the ip adress, I didn't. Sorry to bother you all
once again with this, but the only thing I can do to resolve this
problem, is to restore the existing backup to a whole new server.