Why would a workstation suddenly lose it's IP address? I have had two Win7Pro workstations lose their IP addresses the last couple of days. Why would they do that? The LAN adapter showed "unidentified network" and when I opened the IPv4 Properties window, it was set to "Obtain IP automatically", but all the cells were blank. The only thing we had done to either of these machines was to just restart them. When they came up, they had not obtained their IP's. What should I check, the SBS server? The router? Or, are these two machines just being funky, suddenly? I decided to change to manual IP and entered all the IP, Subnet mask, default gateway and DNS server addresses and the workstation is back on the LAN.