Uninstall and reinstall DUN - Windows XP

TCP/IP cannot be uninstalled on Windows XP. However, you can use the NetShell (netsh) utility to reset TCP/IP. When command is executed, it rewrites pertinent registry keys that are used by the TCP/IP stack to acheive the same result as the removal and reinstallation of the protocol.

1. Click Start > Run
2. In the Run box, type "command" and click OK.
3. At the DOS prompt, type "netsh int ip reset c:\tcpipreset.txt" and press (Enter key)
4. The system pauses for up to a minute while the TCP/IP stack is reset. The cursor returns but no message is displayed.
5. Type "exit" and press (Enter key) to return to Windows.
6. Close all open programs and restart the computer.

See MSKB article: Q299357