one computer causes entire network to go down...

Couple of quick things to check.

First, IP Address of the problem XP machine compared to the ip address of the SBS Server.
(very rare) Does the network card of the xp machine have the same MAC address as the SBS Server's internal NIC?
Did you use the SBS Client Setup Wizard (floppy disk) to join this machine to the domain?
Can another computer connect to the same ethernet connection and work fine?

Checked the MAC addresses, they are not the same.  Also, no other computers seem to have any problems with the server.

One change: I was able to join the computer to the domain this morning, just by changing the computer name in the System Properties dialog.  However, the problem is still here.  One sure-fire way to kill the connection is by trying to work in our Microsoft Access database, which is in a shared folder on the server.  Even trying to open a simple form will cause the network to go down...

any other suggestions?

Thanks,
Chris

Please post an IPCONFIG /ALL from both the server and the problem workstation.  That'll really help to diagnose the problem.

Jeff
TechSoEasy

K, here goes...

SERVER:

Windows IP Configuration

   Host Name . . . . . . . . . . . . : server
   Primary Dns Suffix  . . . . . . . : aes.local
   Node Type . . . . . . . . . . . . : Unknown
   IP Routing Enabled. . . . . . . . : Yes
   WINS Proxy Enabled. . . . . . . . : Yes
   DNS Suffix Search List. . . . . . : aes.local

Ethernet adapter Server Local Area Connection:

   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Linksys LNE100TX Fast Ethernet Adapter
   Physical Address. . . . . . . . . : 00-A0-CC-E3-1D-1D
   DHCP Enabled. . . . . . . . . . . : No
   IP Address. . . . . . . . . . . . : 192.168.16.2
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Default Gateway . . . . . . . . . :
   DNS Servers . . . . . . . . . . . : 192.168.16.2
   Primary WINS Server . . . . . . . : 192.168.16.2

Ethernet adapter Network Connection:

   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Broadcom 440x 10/100 Integrated Controller
   Physical Address. . . . . . . . . : 00-0B-DB-2B-AA-3C
   DHCP Enabled. . . . . . . . . . . : No
   IP Address. . . . . . . . . . . . : 192.168.1.20
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Default Gateway . . . . . . . . . : 192.168.1.1
   DNS Servers . . . . . . . . . . . : 192.168.16.2
   NetBIOS over Tcpip. . . . . . . . : Disabled


WORKSTATION:

Windows IP Configuration

        Host Name . . . . . . . . . . . . : mediadev
        Primary Dns Suffix  . . . . . . . : aes.local
        Node Type . . . . . . . . . . . . : Hybrid
        IP Routing Enabled. . . . . . . . : No
        WINS Proxy Enabled. . . . . . . . : No
        DNS Suffix Search List. . . . . . : aes.local
                                                      aes.local

Ethernet adapter Local Area Connection:

        Connection-specific DNS Suffix  . : aes.local
        Description . . . . . . . . . . . : Winbond W89C940-Based Ethernet Adapter (Generic)
        Physical Address. . . . . . . . . : 00-20-78-18-1C-05
        Dhcp Enabled. . . . . . . . . . . : Yes
        Autoconfiguration Enabled . . . . : Yes
        IP Address. . . . . . . . . . . . : 192.168.16.21
        Subnet Mask . . . . . . . . . . . : 255.255.255.0
        Default Gateway . . . . . . . . . : 192.168.16.2
        DHCP Server . . . . . . . . . . . : 192.168.16.2
        DNS Servers . . . . . . . . . . . : 192.168.16.2
        Primary WINS Server . . . . . . . : 192.168.16.2
        Lease Obtained. . . . . . . . . . : Monday, May 22, 2006 10:56:50 AM
        Lease Expires . . . . . . . . . . : Tuesday, May 30, 2006 10:56:50 AM

Also, how did you join your workstations to the domain?  Did you use the http://<servername>/connectcomputer wizard as required with SBS?

Jeff
TechSoEasy

Turns out it was a Linksys (EtherPCI LAN Card II) with winbond chips...I switched it with a Linksys LNE100TX, and that seems to have done the trick.  It's odd, though, that I'm just now having problems with that NIC - we've been using it for years with no trouble.

I joined the computer to the domain by changing the settings in the "System Properties" dialog, under the "Computer Name" tab.  I tried to use http://server/connectcomputer first, but it would break the network when I tried...what exactly does that wizard do - is there any reason I should remove the computer from the domain and rejoin it using the wizard?

Anyway, (knock on wood) I hope the problem has been resolved, but I'll be sure to let you know if it hasn't.  Thank you for your help, I really appreciate it.

-Chris

There is a lot of reasons that you need to use connectcomputer.  For the "exact" answer to your question, see http://sbsurl.com/connectcomputer

You need to fix this to avoid problems in the future:

The following needs to be done with the client machine:
1.  Log in with THAT machine's LOCAL administrator account.
2.  Unjoin the domain into a WORKGROUP
3.  Change the name of the computer
4.  Delete or rename the following directory C:\Program Files\Microsoft Windows Small Business Server\Clients if it exists
5.  Make sure that the network settings are configured to get an IP address automatically (DHCP enabled)
6.  Reboot

Then on the server, from the Server Management Console:
1.  Remove the client computers if it still shows in the Client Computer screen on the Server Management Console
2.  Add the client with it's NEW name using the Add Computer wizard

Then, go back to the client machine and join the domain by opening Internet Explorer and navigating to http://servername/connectcomputer

Jeff
TechSoEasy

Thanks for the info, I'll add it appropriately (hopefully it will let me).

If it doesn't then you need to find out why and fix whatever is causing the problem.  :-)

Jeff
TechSoEasy