In any version of Windows since Win 98*, just go to the Start button, then Run and type “cmd” in the space (without the quotation marks), then hit enter. In the new window just type “ipconfig /all” (no quotation marks) and hit enter again. You’ll see a screen that looks a lot like this:
CMD does not work on Windows 95, 98 or ME. You have to use "command.com" or "command." IPCONFIG is not a valid command on 9x either, as it's winipcfg, and you release/renew via a button in a small program.