Log on and shut down problems

Hallo,

I have a computer running Windows 98 which I cannot upgrade, on the short
term, to XPP or to Windows 2000 because of some practical reasons that help
no one to explain here.

The computer, member in a domain, sporadically but very annoyingly has log
on problems and does continuously not shut down properly. I tried many things
but did not work.

When I don't load the Vserver.vxd, Vredir.vxd, Dfs.vxd and the filesec.vxd,
the computer shuts down properly. My guess is that to connect the two issues.
Would anyone offer any help on how I can solve this problem?

Much thanks in advance,
Hemin