1. Win98. The attached driver should be fine for Windows 98 SE. Note the lines quoted below taken from beginning of "Netadm9x.inf" file.
;**************************************************************************
; Copyright 2001-2002 ADMtek Incorporated.
; Windows 2000 & Win98 combined inf for NDIS5 driver
;**************************************************************************
2. Install Driver. Unzip contents of "ADM9X.zip" somewhere. Right-click on "Netadm9x.inf" file and select "Install" from resulting context menu. Reboot Windows 98 SE.
3. Device Manager. Open Device Manager to see if network adapter recognized and driver loaded.
a. Right-click "My Computer" icon (on desktop)
b. Select (left-click) "Properties" from resulting context menu.
c. Select "Device Manager" tab.
d. Do you see any yellow exclamation marks, blue information marks, or red X's?
4. Reference:
Device Manager Basics