Hello,
Welcome to the Computer Hope forums. This is the best place for general computer questions.
There are many here who will offer you some practical suggestions. But first they're going to ask you some questions about what you have and what you're trying to do.
So I will start out, I'll make some guesses, and I might be guessing wrong so please fill in the blanks.
First of all are you using a DSL connection?
And if so, does the connection work okay when you go directly from the two wire wireless router to one of your computers? I would assume that it does.
Now then, you have a portable computer, either a notebook, laptop or net book, and you're trying to use the WiFi to get into the two wire router. No?
Okay, I get it. You have another desktop computer and you step some kind of wireless card into it and you can get it to work right. The wireless card is bad. Or you have the wrong driver.
With Windows XP in three important to have though right wireless driver for a PCI card or a USB device that is meant for use as a 802-11 wireless whatchamacallit.