I know some of you are networking/IT guys. Help!

I've got a wireless router/hub at home. I have one machine plugged into it with an ethernet cable and I access it all the time with my laptop, so I know it's working ok.

Here's the problem. I gave my old Windows 98SE machine to my kids and bought a USB wireless adapter for it. The thing is picking up the network, according to the software that came with the adapter (it says it's "associated"). BUT, I can't get online with it. It works just fine when it's plugged into the router with an ethernet cable.

I'm sure I'm missing a setting, somewhere, but I'm stumped.

Any help out there?