Question : Network is dead, BROWSER error?

We have a NT4.0 Network, 1PDC, 10WS all with SP2
Sometimes (once a week) the Network is dead. Clients cannot access the server. On the server everything besides the network works. If I open networkneighborhood sometimes I get the list of all computers but when I click on one the window freezes. Taskman says: no answer
Just before this happens the eventlog has this entry:
ID 8033: Der Suchdienst hat eine Wahl erzwungen da der Hauptsuchdienst beendet wurde.
In english must be somethinkg like: The computer search service (or browser) forces an election because the main search service (browser) was closed.
I checked the registry and my PDC is the Domain Master Browser. I used net stop browser / net start browser, but it did not help. Only rebooting helps.
All WS have MaintainServerList=Auto
Can this be the cause? And why does the MasterBrowser stops working?

Answer : Network is dead, BROWSER error?

Sorry, I don't know a reference.
I have a 3C59X in a NT 4.0 Server and  the same problems.
Now I take the new NIC 3C90X and had no problems.
Try the new card.
I don`t know that Busmaster must be turned off but I don't think so.