To gain access to IPConfig, go to the Start Menu, click Run, type "cmd".
Once you get to the command line, type in "ipconfig /?" to see the various commands. Some common ones are "ipconfig /release" to release an IP and "ipconfig /renew" to renew an IP.
Using the "ipconfig" commands, you can manipulate the TCP/IP stack in Windows XP, such as renewing your IP from the DHCP server.
Fortunately, Microsoft heard our cries and made for us Windows 2000/XP users a form of WinIPConfig built for Windows 2000/XP. This new version is very similar to the one that you are familiar with that is in Windows 9x.
Microsoft supplies it under the name of WinNTIPConfig. You can download it from the Microsoft Web Site by clicking here.