Wireless internet connection / router?

I have a desktop computer (Microsoft Windows XP, 2000) and i need to kow if it has wireless connection to it, but when i go to my control panel and click network and internet connection at the bottom there is a selection that says (Wireless Network Setup Wizard) does this mean my computer has wireless and i can just buy a wireless router and connect my second computer at home to the internet? or what do i need to connect my second computer to the internet? also or should i just buy a USB wireless thing? i need help thnaks.