Windows 98 Login Problem

I'm having an issue with the Windows 98 machines on the network I work on.
It is hard to pinpoint b/c half the time the computers will work (login) and
the other half of the time the computers will come up to the ZfD screen.
(which means that it didn't find the network) Win XP workstations are
logging in with no issues. The only thing we did was adjust the DHCP server
the other week for a ISP change that may have upset the Win98 machines but
we run internal DNS name servers so those numbers didn't change. We are
running Novell Netware 6.5 SP5 with Netware Client 3.4 on Win98.

Nate