Win XP and Win NT

I work on a network for a flower shop, and I’m a novice in networking. I added a new computer to the network with Win XP Pro and also put the system on a router instead of a hub. When I put the cable into the router from the XP computer the NT computer will not show the XP on the network. I ran the network XP wizard, I made the floppy disk for the other machines and when I put that floppy in the Nt computer it tells me that this won’t work with NT. My question is can I network the XP with the Nt computer,If so how can it be done
Thank You
Rod Heikes