My wife is going to kill me - I broke her internet connection

I installed SP2 for W2K on my wife's system, and I didn't choose to save the old files so I can reinstall it. Now her system won't do squat on the internet. It will read files from my system with TCP/IP and NetBEUI, but it will not do anything externally. Here's relevant info:

Roadrunner cable modem service w/ Motorola SB4100

Linksys 4-port firewall/router

cheapo Realtek NIC in my system

SMC NIC in her system

I cannot find a single thing wrong with her network config. It just quit connecting to the internet as soon as I installed SP2. I tried removing and reinstalling TCP/IP and NetBEUI and resetting both the cable modem and router. I even tried connecting her system directly to the cable modem.

I checked the registries, and she has the same DNS servers listed in the same order I do. This smells to me like a DNS issue where her system can't resolve an external domain name, but I have no idea how to fix it if it is.

Geez, I'm having a pretty crappy week, computer-Wise.