User’s right with network connection

I have a client using WIN2000PRO, three user profiles: administrator, guest, user. I wanted to set user as guest to the machine, but after I lost network & internet connection. I can only retrieve the network & internet connection by giveing user asadministrator right, which I really don’t wanted to. I tried to set user with administrator right, then configure the LAN settings. After I changed user back to guest right, I still can’t retrieve the connection. I am out of ideas, please help!