I use my 98 computer on the internet, the stuff I was required was a
1)a notebook
2)A Windows 98 desktop
3)A pci ethernet NIC.
4) 2 ethernet cables.
5) a cheap switch.
so the thing I do is, I get the wifi signal to my notebook, then I connect it btw a ethernet cable to the switch, then the swtich is connected to the 98 machine and voala, the internet is shared to the old computer 😁
also, it's required to make a internet bridge into your internet files (so if I get it, the notebook will be transformed into a switch, and it'll route and give a new ip to the old computer)...
It's not the best solution ofc, I gave up from wifi pci boards since they use alot of processor and most of them only support wifi g or are unstable.
The best solution that I found was using switch replicator, so it can take the wifi signal from other wifi switch and share it btw their ethernet port and even by wifi (doing a wifi extension).
I gave up from anti vírus on that machine, most of the vírus only affect new os, and also I'm only downloading stuff from places like abandonia and oldapps.com, so the chance of getting something dirt is low...
EDIT: I think on the notebook solution, the notebook act as a firewall too, since the antivírus that is running on it filters the stuff that the other computer gets