Windows XP User on network cannot see iDisk or other computers

Windows can access internet through Airport Extreme and can recognize the base station through wireless adapter but cannot access the idisk hooked up through usb on Airport. Receive message - Unable to connect to Idisk ensure that NetBios is enabled and try again. I would like to be able to network all computers together there are 3 mac's and 2 pc's. One pc is working fine and I have duplicated the settings on the second with no change in result. Where do I enable this stupid Netbios?