I have a domain member that could not logon today. When I got in I simply turned off her network adapter and turned it back on (to flush the ip, ect). I probably could have used ipconfig /release and renew but this seemed faster.
Our gateway is 192.168.2.2 and her ip address was automatically assigned to 169.254.254.208. Why/How could have this have happened? Her computer worked fine yesterday and she turned it off last night. However, when she got in this morning she could not logon to the domain because the ip address was outside the gateway.
If this is not the case what you might want to do is check the cable to make sure that it is working properly. Check the patch panel and the port/switch where this user is connected to.