Computer froze then restarted

[sadbluescreener]

I was just downloading the Titan Pack for UT3 and my computer (MSI GX630) just froze and would take no input from me. Then after a while the fan started spinning really quickly then the computer restarted. When I checked the Event Viewer I saw I got an error saying:
"The master browser has received a server announcement from the computer IBUKI-PC that believes that it is the master browser for the domain on transport NetBT_Tcpip_{4F04F4F7-4891-45E1-8017-251488437. The master browser is stopping or an election is being forced."
IBUKI-PC is the name of my brother's computer and we're using the same wireless network.
I've attached a screenshot of the Event Viewer screen. Please help.
My brother says he hasn't done anything on his machine to do anything to mine.

 

[Bobbye]

Once you open the Event Properties, there is a Description at the bottom of the screen (NOT the lines of code)
Right click on the Error> Properties> click on the Copy icon below the down arrow at top right. Paste it here (Ctrl V)
Please copy that- it doesn't show in your screen shot

 

[sadbluescreener]

Log Name: System
Source: bowser
Date: 01/04/2009 11:57:00 PM
Event ID: 8003
Task Category: None
Level: Error
Keywords: Classic
User: N/A
Computer: Wrath
Description:
The master browser has received a server announcement from the computer IBUKI-PC that believes that it is the master browser for the domain on transport NetBT_Tcpip_{4F04F4F7-4891-45E1-8017-251488437. The master browser is stopping or an election is being forced.
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
<System>
<Provider Name="bowser" />
<EventID Qualifiers="49152">8003</EventID>
<Level>2</Level>
<Task>0</Task>
<Keywords>0x80000000000000</Keywords>
<TimeCreated SystemTime="2009-04-02T04:57:00.704Z" />
<EventRecordID>40971</EventRecordID>
<Channel>System</Channel>
<Computer>Wrath</Computer>
<Security />
</System>
<EventData>
<Data>\Device\LanmanDatagramReceiver</Data>
<Data>IBUKI-PC</Data>
<Data>NetBT_Tcpip_{4F04F4F7-4891-45E1-8017-251488437</Data>
<Binary>000000000300280000000000431F00C000000000000000000A000000000000000000000000000000</Binary>
</EventData>
</Event>

Was that what you meant?

 

[Bobbye]

Yes, thank you. Didn't need the code at the bottom though.

This problem occurs when network logon validation is prevented over a network switch. The network switch prevents the server from authenticating the client. The two-way communication session necessary for logon validation is prevented.

server announcement from the computer IBUKI-PC
IBUKI-PC is the name of my brother's computer and we're using the same wireless network.

If I'm reading right, you will need to reconfigure the router and the network:
http://support.microsoft.com/default.aspx?scid=kb;en-us;135464

I also found mention of a patch:
You're going to need to have a look here:
http://www.fileplanet.com/promotions/unreal-tournament-3/titan-pack/patchNotes.html