I service a business with 40 computers that was blocked form Internet access by one PC. The event error read: "The master browser has received a server announcement from the computer TCTRUCKS6-DT that believes that it is the master browser for the domain on transport NetBT_Tcpip~". The network restored after that computer was shut down. It is a peer-to-peer network. The only servers are 3rd party programs. Nobody was physically using the problem PC on the day that this occurred. I noticed that the antivirus (Viper Enterprise, which is the strongest I've seen) was reconfigured just prior to shutdown. The static IP was removed & the workgroup was changed to the default WORKGROUP, but that could have been done by the user previously. It is working normally so far today. I notice in the Windows log that special privileges were assigned to a new logon many times on this & other PCs. What should I do at this point to track this down & prevent recurrence?