I do a bit of work with routers but not had this problem come up before. The Internet is provided by NTL cable modem. It is connected to a Linksys WRT54GS router which gives out a wireless signal to two laptops (both running Vista). All the computers can connect to the router but only one has an Internet connection. I believe it is a problem with the DNS server of the router. I have reset the router, powered it down, turned the modem off etc etc, didnt work. Used a different router (Belkin) but the same problem happened. Sometimes only one of the laptops will work, it is pretty much pot luck trying to find one that works. I have set up preferred DNS IP addresses on the router, I have changed how many clients are allowed onto the router, etc. I have discovered (as I have been writing this)that the computer that connects to the Internet is directly connected, it wont connect to the router. Does anybody know how to solve it? I have looked on the Internet but struggle to make sense of DNS or the tutorials are half done. Thanks

You need to be more descriptive about the problem. Your router is not the DNS server, DNS server is located on your ISP side. Did you check whether the machine has an IP address assigned by the router's DHCP server? when you can not reach the internet, try to ping a domain name via cmd, for example ping www.google.com if the ping works, then its NOT your ISP's DNS server problem, its your local computer's problem. Make sure NAT is enabled on your router (some routers do have this option, while others don't, so check your router's documention)

I had that problem too. What worked for me was changing the security settings if you are on WEP 64 do WEP 128, or vice versa.