I would'nt trust Win98 drivers, if you don't have the driver disk, try and get hold of updated ones online - for older stuff driverguide.com is great. The login and password are:
Username: drivers
Password: all
This is not backdoor or anything dodgy, it's the details they give you when you ask for a guest account.
Other than drivers, it could be your network settings, like maybe NetBEUI was installed before and now it's not, or maybe you have some gateways that are no longer installed. Network cards are strange beasts, 1 stupid setting can stop them from working.
Van-B
Muhahahahaha.