I have a laptop running Windows 7 SP2 that would not install updates from our WSUS server running Server 2012. I found that it would not ping the server or UNC to the server either. Plus I could not ping or UNC to the laptop from the server. I wiped the laptop and rebuilt with the same result. There is no firewall between them. There is no DHCP filter for the MAC address of either.
Both are on the same 255.255.252.0 subnet tho the server is at 2.25 and the laptop used DHCP, which it can get for some reason from the same server. I have found that the laptop can access any other server on the 192.168.2.x subnet, just not the server at 2.25.
Not sure where else to look or what to test. I really would rather not change the IP address of this server just for one laptop that won't play ball.