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Windows System Error – There is an IP address conflict with another system on the network.

Windows System Error – There is an IP address conflict with another system on the network.

I recently diagnosed a fault in my server NIC which was a 3Com PCI card. I replaced it with an Intel Pro/1000 T. The problem is that the original card had a static IP address of This address is required for the new Intel card and an error message is displayed that there is a conflicting IP address in the system.

The conflict is not that another node has the same address but it is as a result of the 3com card not being uninstalled correctly. The operating System is Windows 2003 SBS Enterprise Edition

My question is, how do I remove the original configuration settings which will remove the error message. The network is working fine other that the error message. The system settings shows the 3Com card hidden but will not allow it to be removed. When I attempt to uninstall the device, an error message “Failed to uninstall the device. The device may be required to boot the computer” is displayed.

Any help would be much appreciated.
3 Solutions
Pete LongTechnical ConsultantCommented:
working from memory bear with me

start > run > devmgmt.msc

View > show

then its either hidden devices or all devices, you can then see the old network card and right click >uninstall it
Pete LongTechnical ConsultantCommented:
view > show hidden devices
Pete LongTechnical ConsultantCommented:
Right CLick My computer > Properties > Advanced > Environment Variables
System Variables Section > New

Create a new Variable Called

Set it's value to: 1
Reboot your machine
Goto your device manager
Show all hidden devices
Now you can see all devices you ever installed
Remove the NIC as usuall
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Pete LongTechnical ConsultantCommented:
-------------Method 2-------------------
To get rid of that unwanted driver, device, or service:
1) Open the "Start" menu and choose "Run..."
2) Type in "cmd" (without the quotes) and click "ok".
3) At the cmd prompt, type in "set devmgr_show_nonpresent_devices=1"
(without the quotes) and press enter. (Note that nothing seems to
happen--this is ok. We are actually setting an environment variable
 which is going to help us to see hidden devices)
4) On the next cmd prompt line, type in "devmgmt.msc" (without the quotes)
 and press enter. This will launch the Windows Device Manager Console.
5) In the Device Manager Console, from the "View" menu, select
"Show Hidden Devices".

Now, as you expand the different drivers and devices in device manager
you will see not only the items that Windows currently detects as
 installed on your pc (these are the usual items displayed), but you
will also see drivers, devices, and services which have been loaded in
the past but were not uninstalled or are not currently started. You can
find your offending device, right-click, and choose "uninstall" to remove
it from the system completely.

Be careful though; you should note that non-loaded devices, drivers,
and services are "grayed" out, but that doesn't necessarily mean that
you should delete all of them. Only remove items you know you don't need.
And, be careful that you don't change too many devices or you might need
to re-activate your Windows installation.

Last thing, if you accidentally exit the Device Manager Console you will
need to start over again at the cmd prompt. To close the cmd prompt window,
type "exit" (without the quotes).
Leon FesterIT Project Change ManagerCommented:
The error that you are getting is quite common in that scenario. i.e. when replacing a network card.

Your system will continue to work correctly with the old NIC card/settings as is.

The only way to uninstall the card is to put the old card back in and then remove it.

This behaviour is by design, and dates back to WinNT 3.1, when you HAD!!! to absolutely remove the OLD NIC first, reboot and then install the new NIC.
Yes. Whan dnt_localboy said is correct. put back old card. Once os detects, uninstall the nic from devicemanager. Shutdown windows. remove old card. restart os. See any error message & check the device manager. If cleared, shutdown. Insert new Intel card. On back.
bushsubaruAuthor Commented:
Thanks everyone for the advice. I suspected that the only solution was to put the old card back in the system and uninstall in correctly. I will let you know once I give it a try. It is odd that Microsoft haven't devised a routine which will remove spurious drivers and settings of this sort. Then again, logic isn't one of Microsofts' stong attributes.
bushsubaruAuthor Commented:
Hi Evereyone, Your comments were valuable and allowed me to test all conditions which might have lead to the problem.

However, I finally resolved the problem by firstly NOT considering that the server or any connected node was the problem but simply that I had forgotten about the managed switch which had been assigned the same IP address as the server NIC.

My fault, as I should have considered this before asking the experts.

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