Check your bindings. Right-Click on your network
neighborhood, then click on properties. That will pull up
your Network, and Dial-up connections window. Click on
Advanced menu at the top, and then select advanced
settings. In the "Bindings for Local Area Connection"
list near the bottom. Make sure that for your "Novell
Client for Windows" bindings are set with the NWLink
IPX/SPX/NetBIOS protocol is above TCP/IP, and checked.
For the Client for Microsoft Networks, make sure that it
is the opposite (TCP/IP is on top). If they are not like
that, then it will try to use the incorrect protocol
first, and then pick the correct one. There's also some
registry setting for when you login, but I don't remember
where that is. SP4 probably reset your bindings. If that
fails, format your novell network, and install microsoft.