Accessing a Airport Network with a Windows 98 PC or laptop
Windows 98 does not have native support for wireless network.
What this means is that, unlike Windows XP, you can not plug in a wireless adapter and expect Windows to recognise it and start working.
You will need to install some kind of software configuration utility that came with the adapter. Each manufacturer has their own software so as a result the process of using these utilities to connect a Windows 98 computer to an Airport wireless network will be different and so no generic guide is available.
Having said that you may find the following information on things to watch for useful.
1. Using WPA on the Airport
WPA is a relatively new wireless encryption protocol and though many cards will have WPA support in Windows XP, most do not have WPA support for earlier versions of Windows and so you will have to use WEP.
2. WEP Key in plain text and not HEX (or not "correct" length)
Remember that the WEP key will depend on the level on encryption been used, and if you are using 128 bit that the key will be a 26 digit hexadecimal number and not the plain text you used in the AEBS, unless the plain text password is 13 characters.
If you are using 64 bit encryption, requiring either a ten character HEX key (or 5 character plain text password) then you may want to upgrade to 128bit as there have been some reported issues with connecting a PC to a 64 bit encrypted AEBS.
If you enable WEP on the AEBS, you need to note down the Hex Airport Network Password, if you are using 128bit encryption this will be a 26 characters. If you open the Airport Admin Utility, you need to click a button called Password depending on which version of firmware you are using.
The Wireless ASCII Equivalent Password is the plain text network password you use to access your Airport network with a Mac. An example plain text password could be: airportpassword. For 128bit WEP networks you should choose a 13 character ASCII password this in theory is hashed in the same way by all vendors.
The Wireless Hex Equivalent Password is the hex version of the plain text, and this is what you would use with your PC. An example HEX password could be: BAC34DAAAB56B7CADA336B23DA
Not all utilities even support the 128bit 13 character rule (as they don't use algorithms in which case you must use the 26 character HEX key. If you are using a 40bit 5 character password then you must use the 10 character HEX key.
3. Key #1 is not used
Ensure that when you enter the key you enter it as Key #1
4. IEEE 802.1x authentication is on
Ensure that the Enable IEEE 802.1x authentication is disabled.
5. Bridged Connections
For some reason Windows allows you to bridge your connections (wired, IEEE 1394 and wireless) and this will stop your Windows PC from being able to get a valid IP address. From the Network Connections window delete all Network Bridges.
6. Authentication Mode is not set to Shared
If you are using AEBS firmware 5.1.1, 5.2 or 5.3. All other versions of the firmware allow Open authentication, firmware 5.4 allows both Open and Shared.
Ensure Network Authentication mode is set to Shared.