How to Reset Internet Protocol (TCP/IP) in Windows XP
Contributed by mikejc 
August 24, 2004 
Tagged: Windows networking
When viewing the list of components for a network interface, you may notice that the Uninstall button is disabled when Internet Protocol (TCP/IP) is selected. In Windows XP, the TCP/IP stack is considered a core component of the operating system; therefore, it is not possible to uninstall TCP/IP in Windows XP.
In extreme cases, reinstalling the Internet Protocol stack may be the most appropriate solution. With the NetShell utility, you can now reset the TCP/IP stack back to a pristine state, to the same state as when the operating system was installed.
The NetShell utility ( netsh ) is a command-line scripting interface for the configuring and monitoring of Windows XP networking. This tool provides an interactive network shell interface to the user.
In Windows XP, a reset command is available in the IP context of the NetShell utility. When this command is executed, it rewrites pertinent registry keys that are used by the Internet Protocol (TCP/IP) stack to achieve the same result as the removal and the reinstallation of the protocol.
mike