If you are not going to share an Internet connection and just want to share files between a Win 98 and a Win XP computer, install just the TCP/IP protocol on both computers (I have found that XP does not like NetBEUI). Assign private static IP addresses to the instances of TCP/IP bound to the network adapters: e.g., 192.168.01 to one of the computers and 192.168.0.2 to the other.
You may also have to activate the Guest account on XP computers... Start, Control Panel, Category View, Performance and Maintenance, Computer Management, System Tools, Local Users and Groups, Guest, and uncheck Account is disabled, if it is.
On XP, right-click My Network Places, Properties, select TCP/IP associated with the network adapter, WINS tab, and select Enable NetBIOS over TCP.
Drive sharing on the XP computer: My Computer, right-click C:, Sharing and Security, Sharing. It had drive C: shared as C$, the default share. This share is not visible to other computers on the network. Clicked New Share and added a new share name of “C” without the dollar sign. Clicked Permissions and verified that Everyone had full permissions. OK, OK, Apply, OK. Larry