>I have not only unpluge many times but also change Network card. the problem is when i assign an IP ,that i have assigned to 3Com, Windows2k shows a message that this IP assigned to 3com do you want to assign. Now i don't have 3com Card and I can't assign this ip to new NIC.
>The question is how to remove physically 3com ip Entry. So that i can assign this number to another card


If you still have the 3com card, try putting it in again and then removing it. If you cant do that, run regedit and do a search for the IP address you need to remove. You should be able to delete it from the registry.

It should be under HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces