I have an unusual networking problem on a mixed Windows network. I have 7 hard-wired computers on a peer-to-peer network plus 2 printers and an Apple Airport. 4 computers are Windows XP SP3 and 3 computers are Windows 7 Professional 32. I use one of the W7 computers as a server and access it from most of the others. I regularly access the server from 2 W7 computers and 2 XP computers. The problem is that each of the XP computers gets intermittent data from the server from within the program that is seeking the data. The programs are not the same on the 2 XP machines. I can see the data from Windows Explorer on the XP machines, but the programs have varying errors in reading and manipulating the data. The problem is intermittent. Usually I must reboot the W7 server to solve the problem once it has started. My router is a SonicWall. In an effort to solve the problem, I have forced the server to act as the browser master, and have completely replaced one of the XP machines and did a clean install on the OS. I have no problems with the server data when accessed by the W7 machines.