W7 - XP can no longer see/share

We have been using a Windows 7 machine and an XP machine for some time now - they are using the same workgroup name, and were sharing files using the Public folder on Windows 7, no problems. The XP could also connect to the printer, which is hardwired to the W7.

They are both using wifi in our building. The wifi, which is owned by the landlord, used to be called Ourwifi. A couple weeks ago, the power went out in our building and then there was a problem with the wifi and the internet/cable company came out and changed it. It is now reconfigured as Ourwifi2. It is password protected.

Since that change, both the W7 and XP computers are able to access the wifi and use the internet, but now they cannot share files.

As far as I know, nothing on either of the computers settings had changed.

The W7 computer was turned OFF when the power went out; the XP most likely was ON (because that user tends to leave it on all the time).

Since I've been trying to reconnect them, I may have changed something by accident.

So here are the settings in the W7:

• Network and Sharing - Under advanced sharing settings, password protection sharing is OFF under "home or work" as well as under "public."
• Workgroup is listed as the same one as the XP computer (ourwkgrp).
• In W7, under active networks, Ourwifi2 is listed as a"work network"
• W7 has Norton running; I'm unsure if it has had any auto-updates that may have changed accessiblity settings. I can't find in the Norton settings how to add all those TCP and UDP numbers suggested in a post elsewhere that might help it find the XP machine.

On the XP machine --
XP can see (or thinks it sees) the W7 computer over the wifi -- if I look at "view workgroup computers" in the XP -- W7 shows up, but if I attempt to connect, I get a message saying it is an invalid path, cannot be viewed over the network.

XP cannot print to the printer connect to W7. It can't see the printer b/c I can't expand the W7 folders that show up under "view workgroup computers."

TIA for any suggestions -- I'm rusty on all this, so please include detailed instructions on how to access anything if you send "change this to on," etc.

Thanks!
~W

Disabling the Norton firewall totally disabled the wifi antenna. If I disable Norton Services, does that leave the computer unprotected? Or just those little add-ons Norton has installed?