Adding a print server killed my internet

My network consists of a DSL modem connected to a SMC wireless router (802.11b) and a network cable running upstairs, which connects to a switch. There is is 2 computers hooked up to the switch.

The problem is that I replaced my switch with a router that was sitting around (D-link DI-704p, older one) That particular router had a print server function, and has a built in 4 port switch. I replaced my switch with it, setted up 3 computers so that it could use the printer connected to the router.
Computer A and B is running Windows ME and uses wired connection. The notebook (dell C400) uses wireless networking. I installed the printer server software and did what the instructions said. Computer A, could get on the internet, but can't print. Computer B could print, but can't get on the internet. Laptop couldn't connect to the internet, but because its network is wireless, it doesn't go through the D-link router. I didn't try the printer because I was already fed up. I pinged the router, and it responded without loss, all the compouters are visible on the network. So the network actually works, but why didn't the internet work? I restarted both of the computers several times. I put my old switch back and everything was fine again. Any ideas? There are a total of 5 computers on the network, but I haven't done anything to the other two. If you need model numbers, or specifications for the computers to diagnose the problem, please ask. Any help is appreciated.
Thanks
Howard

make sure the dhcp is disabled on the router you dont have the dsl hooked up to. then release and refresh the ips on your computers.

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