Iinternet Gateway not discovered

I just replaced the motherboard in my computer and reinstalled WinXP SP2. I
installed networking components (Simple TCP, UPnP, Peer to Peer, and
Internet Gateway Discovery and Control).

The computer does not list a Internet Gateway in Network Connections, nor
does it list the Linksys router (BEFSR81). The previous Windows installation
had listed these.

I am unable to use Windows Messenger Remote Assistance to help my parents
with their computer, something I had done routinely prior to re-installing
Windows.

Reading the Windows website, it says that Internet Gateway Discovery isn't
required for XP, but I'm wondering if it's absence is related to being
unable to use Remote Assistance, and if there is a fix.

Thanks,
Fitz