Question : domain controller is unavailable

i have 2 laptops configured in my domain.
and i have several desktops , in don't face any problem with desktops

but face problems with laptops when logging in it says dc not available.your computer account cannot be found in domain
i did ipconfig/flush and registerdns, it is set to DHCP

but when i unplug thecat5 out , it logs me in but when i plug the cat5 in network port of laptop in it doesn't log me in

Answer : domain controller is unavailable

If it is only for one user, see if the error follows the user or stays with the machine.  Have a known good user sign onto the errored user's computer.  Also, have the errored user sign onto a known good computer.  Post results.

Justin