I can't tell from your post how the XP machine is supposed to connect to the old router so I'm left with one lone idea.
Google XP NETSH RESET and hope.
I bought a Linksys WRE54G Wireless-G Range Expander 1.0 in hopes of using it with a Netgear WG111v2. I downloaded the firmware from the Cisco website onto the desktop computer that runs my wireless network. I used the Linksys "smart wizard" to try to configure the range expander, and at the end of the process, I got a message saying it would not support WPA security. Linksys wants me to pay $30 or more or they won't help me with set it up because it is out of warranty, so I am willing to just resell it on Ebay and forget the whole idea of using it.
The problem is that now I cannot access the Internet from my Windows XP desktop computer. I am posting this note from a Vista laptop on the same network. I got a message on the desktop earlier saying there is an IP address conflict.
I tried using the Reset button on the wireless range expander to resolve the conflict but this seemed to have no effect. I have unplugged the router and restarted the desktop several times. I looked for a way to uninstall the firmware from my desktop, but it does not appear under Add/Remove Programs or the device manager.
How do I get Linksys off my computer to get my Netgear router working again? Thanks in advance.