From a newsgroup post: "Whenever a server starts up, it calls for the Master Browser. If none is found, an election is held. The "winner" is based on who best can fulfill this role; O.S. is first rank. WINNT Server beats WINNT Workstation, which beats WIN98SE which beats out WIN98, which beats out WIN95. In addition, when a WINNT Workstation boots up and finds that a WIN98 client is the Master Browser, the WINNT Workstation client forces an election. There are also two registry entries that can be edited, depending on what you want to do:
(1) MaintainServerList is located at HKLM\Sytem\CurrentControlSet\Services\Browser\Parameters. There are three settings: no (can not be a browser), yes (very detailed, basically this would be the favored child in a tie if it got that far, for example, if two WINNT Servers were equal as far as everything to that point goes, the one with this registry entry would win the tie, and auto (will act as browser if asked by Master Browser). NT Workstations have it set to NO and NT Servers have it set to YES by default.
(2)IsDomainMasterBrowser, which is located in the same location. Here there are two possibilities: yes or no. The default is NO for all computers. If this key is set to YES there are two things to consider: the first is that this machine will have an advantage in an election and the second is that when this machine boots up it will always force an election".
This event appears when the browser has attempted to promote itself to the master browser more than 25 times and failed. See MSW2KDB
for more details.