I solve this with ethernet wifi clients. I don't know what country you are in so I'll give one example so you can start looking.
There are others by other makers but this neatly sidesteps the OS issue.
I have an old Compaq desktop computer that I would like to add wirelessly to my home network. The computer is running Windows 98 (not 98SE). I need to buy some type of wireless adapter for the computer to connect it to the network. Do you know of a product that is compatible with Windows 98?