I have two network ports built into my motherboard. One went dead (don't know why), so I switched to the other. After that, I can get to the internet but I cannot get to files on other machines or the network file server (a western digital USB network server connected to the router). My other machines have no problem getting to anything and can get to my Win 7 machine as well. I can ping the other machines and file server by name and IP, but when I try to connect with a standard \\fileserver\share UNC, I get an error stating it is not accessible or I may not have permission. This all worked before. I can see the Windows Media Server share and get to those, but no file shares. I have access permissions (it's wide open) and the other machines on my network are connecting without a problem.
As mentioned, everything worked fine on my other network adapter on the mother board, before it went dead.