There is a newer tutorial available which also allows Windows Update and so on, better follow this one.

You want to install Internet Explorer 7 oder Windows Media Player 11 on your Windows XP computer, but without validating your Product Key with the WGA (Windows Genuine Advantage) tool (I don’t ask for reasons…)? Then I’ve got the easiest hack for you to make your Windows genuine!

To bypass the WGA check, you can simply tell your computer, that the check has previously been made, and that its result is that your Product Key is correct. The information about this is stored in your Registry, so by adding some more entries to it, the installation of WMP and IE will think you passed the check.

Download it here: WGA bypassing file (registry hack)

You may only download and use this file if you own a legal and activated version of Windows XP! Do not use it for illegal purposes!

After downloading the file, extract the “wga.reg” file and doubleclick it. Confirm the following question whether you want to insert the information into your registry. Now your WMP or IE installation should work fine!