http://www.microsoft.com/technet/net.../vista_fp.mspx

http://windowshelp.microsoft.com/Win...051033.mspx#E4

The two links above, which I found at this site, were a lifesaver to me.
Similiar to many other people here, I was installing a new PC with Windows
Vista (Premium) onto an existing small interoffice workgroup where all the
existing PC's are running Windows XP (Home & Pro).

Initially, with the help of the first URL, I was able to recognize all the
XP PC's, access their public folders, and access their printers. But for the
life of me I couldn't get them to see the new Windows Vista PC. After a lot
of post searching and tinkering around, I finally associated the problem with
the McAfee Antivirus that was pre-installed on the new PC and the UDP/TCP
configuration information that is under the heading "Using a Third-Party
Firewire" at the first URL [near the end of the web page].


The below fix applies to McAfee Anti-Virus v7.1
------------------------------------------------------
Open McAfee
In the display box click on INTERNET & NETWORK Configure
In the display box open "Firewall protection is enabled" Advanced
In the left column click on "Security Level" Select "Grant Full Access" Apply
In the left column click on "Trusted & Banned IPs" Check the line with your IP address ranges Apply
In the left column click on "System Services" Check necessary UDP/TCP ports as per list for your condition Apply

Note that with the UDP/TCP ports, the list generated by McAfee doesn't
really define whether it is UDP or TCP, so you are really selecting by port
number.


I hope that this helps someone and I really appreciate all the help others
have given me here!