I have a 4 pc peer-to-peer network connected via a hub. All have been recently upgraded from Me to XP. Three can see and talk to each other properly. However one pc is giving problems. After installation it could not access any pc on the network. Adding a new user called "test" made it act as follows. One of the other pcs cannot find it at all. the other two get asked for a user name and password. The problem pc can access all pcs and copy files to and from them. All the pcs, including the one that cannot see it, can ping it. All pcs have manually selected IP addresses in 192.168.254.x range. All pcs can acess internet via router attached to hub. Removing "test" reverts back to it not seeing any pc. All pcs are set as administrators and no passwords have been added to any of the pcs. Confused? I am. Any help would be gratefully received.