Dell PP10L won't coonect to wireless?

So I have this Dell PP10L computer that I just recieved from my cousin, but it will not connect or even find my wireless connection. I have tried everything I can try and still nothing. It works fine with a wired connection. It says it has a 3Com 3CN3ACx556 LAN/modem in the PC. Not sure what that means. This computer is running Windows XP Professional. The service tag is BJK0D01 just in case it is needed. By the way I do not know much about computers and I do not know anything about laptops, so please use as little words as possible. lol Thank you.

 

The system is a Latitude C600, right? I had to run the service tag to find that out...PP10L is an internal part number.

Seeing that the system is so old, it probably doesn't have a wireless card installed. You'll need to get a PC card for it, such as a Linksys WPC54G or WPC54GX, which can be found for pretty cheap. However, I'm not sure I would invest any money into a computer that old (system shows as shipped 2/2/2001)...modern laptops have wireless cards built-in, so a wireless PC card wouldn't have much use other than just for that laptop.