The desktop probably does not have a wireless network card. You will have to get one or run an ethernet cable from the router to the computer. You can get a wireless adapter that plugs into a USB port which may be best for you.

run belarc and see what it says is on that pc, as Bob said if it does not have a wireless network card in the pc then you can not use it wireless, you can still hook it up by ethernet cable. If you find it does not have a wireless card you can buy one and install it or as mentioned get one that plugs into the usb port of his pc.
Belarc Advisor
running belarc will tell you exactly what is in the pc so you will then know if there is a wireless card and what slots are available to put one in.

How old is the desktop and what windows is it running?

also once you get the pc set up with wireless card you will need to enter your wireless network password into that pc so that it can gain access to your network.
You should not have to run the disc that came with the router at all. If the pc has wireless card it should see your network and then ask for the password once you select that network from the list.

So is a wireless adapter much different from a router? I guess I thought they were like one in the same. I did see one at the store today but didn't get yet ... I wanted to find out first what the difference is since I had thought a router would have been the remedy.

you need a Wireless Card for the pc...

you can get usb or pci Wireless Cards..

google ---Wireless Card

Router and wireless card are different. The router enables you to use your internet connection on more than one computer but each computer has to be plugged into the router with an Ethernet cable or have a wireless card to receive the signal without being plugged into the router.

Most all laptops have wireless cards built in, but few desktops except for newer models have this. As several have pointed out, you can get either a pci card or a usb card (adaptor). Then the computer with a wireless card can connect wirelessly via the router. If no wireless card, then an ethernet cable is required to connect the computer to the router.

For example, my desktop does not contain a wireless card, so I have it connected to my router via an ethernet cable. My laptop has wireless installed, so it connects wirelessly, and I use it in another part of my house away from the router and the desktop.

what you need is a dongle, I have 4 PC's on my home network, and my older desktop was not WiFi enabled, so it now connects thru my lil dongle which sit's in it's charger, and cost me about $30 check out this website to learn about them

Here is a link that might be useful: Dongle

they have not even told us if there is a wifi card in the pc.

We need to know what is already on the pc which is why it is a great idea to run that belarc scan and then let us know so we can better help. You can download belarc on to a disc and use it from there to install it on that pc.

when our questions are not answered it becomes futile for us to try to help, and we may make the wrong assumptions.

Have they tried connecting that pc using an ethernet cable to the router ? to see if there is a connection that way.
How old is the desktop is this someones used pc or is this a brand new one?

My cd rom drive is out of commission on my desktop. The one in question that was given to my son is at the other end of the house. I was going to originally use that one but decided against it. I did actually hook it up in here and it did connect to the internet. Is there a way to tell if there is a wifi card that way? How difficult is it to install one?

It was my fil's used one but I understand that he had it for only a year or two. It has Windows XP.

Sorry to be so dense but I've never done this before and really don't have a clue on my own. Thanks for the help.

Here's a link to wireless adapters at Amazon.com. You would want to get one that plugs into a USB port. I see the second one listed costs $12.99 and looks like it gets good reviews by users. You just plug these into a USB port and then, if they are not plug and play, run the software that comes with them to load the driver.

ok that helps now we at least know it is an older used desktop and not brand new. some of the newer ones do come with wifi cards installed.

I would go with one of the usb type much easier for you to use, just plug it into the usb port on the desktop and then you will need to have it find your wireless network and when you select it you will need to enter your wireless networks password.

Personally I prefer the type that have a cord that goes to the usb plug rather than the little ones that look like a flash drive and plug directly in, with the cord type you can move it around on the desk to find the best spot for reception. this is what I mean
USB Wireless WiFi LAN Adapter With High Gain 7dBi Panel Antenna or this
Belkin

and not this type
WIFI USB WIRELESS

the ones that plug right in like that can be easily bumped and there is no way to move them around for better reception. Just a personal preference, but sometimes placement does matter.

the type that you would have to open your pc case and install into one of the slots is like this
Wireless-G PCI Adapter

My desktop XP about 9 yrs. old which is now in our guest suite way over on the other side of the house connects beautiful with the dongle, which I first looked up online, then purchased at a local store the name is D-Link, see pic. it sit's in a holder and plugs into usb port on back of PC. I am sure this is all you need..

I just want to say a big THANK YOU to everyone! I appreciate all of your help - he can get online from his room now!

Still cannot print, but the main problem is solved! :)