Router/Modem Problems

I am having problems with a Westell VersaLink Model 327W which acts as both a modem and a wireless router. Its wireless network has WEP protection.

A Vista machine is connected successfully to it on LAN via a CAT5 cable.

A Windows XP machine is connected successfully to Versalink wirelessly; however, it cannot connect to the Versalink on LAN. When I try via LAN, windows just tells me that a network cable is unplugged. I know the cable works fine in other conditions.

A HP laptop running XP which has connected to other networks both on LAN and wirelessly can not connect to the router/modem either way. For LAN, the network cable also seems unplugged. For wireless, I use Windows to configure my wireless network settings, and when I try to connect, it just says "waiting for the network" for a while before giving up.

I'm trying to get the XP machine to connect to the router on LAN and the laptop to connect either way. My ISP is verizon and I've spent countless hours with their tech support to no avail. Can anyone help? Thanks in advance.