If you're going to do this you need to understand that this will cause Media Center to stop functioning correctly.

You can bypass the WMP installer's system checks, enabling you to install it with barely more effort than a standard installation. If you'd rather find a lower cost alternative that allows you to use both your computer's media center features and Windows Media Player 11 for streaming video you have another choice. The worst part is, all you're really paying for is an update to Media Center. This means it won't come with support if you run into problems. Plus you'd have to buy an OEM System Builder version of the software, because no retail version exists. In reality this isn't an upgrade as you'd need to install it as a new operating system. The easiest option is to simply upgrade to Windows XP Media Center Edition 2005. As a result, even if you could install WMP 11, it would cause the Media Center program to stop working correctly, therefore the installer simply stops when confronted with your operating system.

Unfortunately, Microsoft has decided not to continue the upgrade path that allowed users of early MCE computers to upgrade as far as the 2004 version. This new WMP code was also used as the basis for Windows Media Player 11, which is starting to be used in DRM protected streaming video, most notably by Netflix. Windows Media Player is at the heart of the Media Center application that creates what Microsoft calls a '10 foot interface'. In 2005 they released a new Media Center Edition, still based on Windows XP, but built on different Windows Media Player code. How Did This Happen?In 2002 Microsoft released the original version of Windows XP Media Center Edition (MCE), which they continued to develop through 2004. As the error explains, versions of Windows XP MCE prior to 2005 aren't compatible with WMP 11. If you try to watch a movie you'll be greeted with a message that you must upgrade Windows Media Player (WMP), which will be followed by an error when you try to do so. If you have a computer running Windows XP Media Center Edition (including earlier versions upgraded through Service Pack 2) and you're a Netflix customer, you may have found that you can't use their Watch Instantly streaming video service that's included with your monthly subscription.

Windows media player 11 windows xp