Once again XP at work defeats me. The design PC was connecting to the internet yesterday, and today it doesn't. It can see my PC, and I can see it. Both PCs can print off each other's printers. My PC can see the internet and the router. The other PC can't see either, or send email.
The settings are the same. Turning off the firewall doesn't help.
I checked the filtering on the router, which what caught me last time.