Netgear wireless LAN problem

[Mourndark]

Hello all (essay ahead!)

I have had a wireless Netgear router set up and working on 3 computers for some time. I have recently tried to add two more computers (A homebuilt desktop and a Lenovo 3000 laptop - both on XP SP2), and although both can see the network, neither can connect properly. I have a WEP key enabled (32 char).

I have run the windows network setup for both, and put in the network key, but I keep getting the message "Limited or no connectivity" In the network settings, neither of the computers has been assigned an IP address in the correct range (192.168.0.*), and do not have an address for the DNS server or gateway.

I have tried disabling the Windows firewalls, with no luck.
I have tried using both windows configuration and the desktop's Belkin 3rd party configuration tool with no luck.
I have tried using a memory stick copy network settings across using the windows wizard, with no luck.
I have tried manually inputing IP, gateway and DNS addresses, although that shows up as connected, it cannot access internet or shared areas.

Can anyone suggest anything else?

Thanks in advance...