Network Clients Internet crawls after server is offline

I have an issue where my XP clients slow down considerably when this older win2003 server is offline or powered off. Example is launching the internet takes almost a minute to come up when it is instantanious when this server is online. This server is not a domain controller and sits in its own seperate domain. It isn’t the DNS, DHCP or WINS server.It sits in its own domain. I am stumped on this one.