Sharing internet connection

Archived from groups: alt.comp.networking.connectivity (More info?)

I've got two desktops and a laptop in the house. We don't share files or
printers but share an internet connection. The cable comes into the cable
modem (Motorola Surfboard), the cable modem is connected to a Linksys WAP11
Version 2.2. The desktops have Linksys Wireless USB network adapters
(WUSB11 Version 2.5). The laptop uses a Linksys Instant Wireless Network PC
Card (WPC11). OS are as follows:

Laptop: XP Pro SP2
Desktop 1: XP Home SP2
Desktop 2: XP Pro SP1

The problem is that a few weeks ago Desktop 2 was no longer able to access
the internet, despite the signal being adequate. Internet access on the
other two machines was and remains fine. I thought at first a software
problem, and had been planning to upgrade to XP anyway, so last weekend I
reformatted the hard drive and installed XP Pro SP1. The only other thing I
installed on the machine was the USB Network Adapter driver. Still can't
get the internet, but the machine has a strong connection to the network.
Other points:

- As with the working machines, it is configured to look for an IP address
automatically, and other settings are in accordance with what my ISP
(Comcast) calls for.
- Signal strength is not an issue. I moved the WAP right next to the
machine, maxed out all the signal strenght indicators, and it didn't help.
- The network adapter is not the problem - I swapped it with the one on
Desktop1; 1 continued to work and 2 still didn't.
- All drivers are up to date.

Sorry for the long post, but I would appreciate any thoughts on what's going
on here, and what to do about it. Thanks!

Nick