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. However, the TCP/IP stack can be reset to the state when the OS was first installed.
•Go to Start Menu -> RUN
•Type "command" click OK•In the new window that pops up type this "NETSH INTERFACE IP RESET LOG.TXT" (less quotes), then press enter.•Reboot, if you like.
More detailed information can be found in this MSKB article:How to Reset Internet Protocol (TCP/IP) in Windows XP (Q299357)