I have a network with a 2003 sbs and xp Pro SP2 clients. We bought three Windows Vista Laptops and joined to the network. 2 of the vista computers can see and ping all the computers on the network but cannot access them and the Xp computers cannot access the Vista Laptops either. One of the Laptops does not see the XP computers but only the Vista Laptops. The computers are all in the same workgroup called XPA and have dhcp assigned IP addresses. I have downloade and installed the LLTD on the Xp computers but still no luck.
I was the first in my company (I telecommute) to need a new system, and got a laptop with Vista. We were completely unable to network it nor access the shared drives. I ended up having to swap laptops with my husband who had XP.