WORK-GROUP NETWORK ISSUE

I just setup a work-group network with 4 client computers and a network printer. All computer have dynamic ip expect the printer that have static IP and they all runs on windows operating systems and as follow. 2 computers runs on windows vista home premium, 1 windows 7 and one windows XP. Each time i connect the computer running windows XP to the network, every other computer on the network get disconnected and the computer won’t receive ip from the DHCP server as well. I would like to know the cause of this problem and a possible solution.