It is quiet a natural thing to happen because the version of IE that you have is newer than the version you are trying to install and Windows prevents this. Tell me one thing that -does it really matter which browser you are using? Are you not just wasting your time upon an unnecessary thing? If you are too much inclined upon installing IE8 beta then uninstall your present Windows XP SP3 and install a previous version and then try reinstalling your beloved IE8 beta. By the way I use Firefox and I'm satisfied - you too can download it for free from Google. Anyway if you want to take your mind off this mess and want to know some cool ways to make money online then visit my blog titled - Make Money Online .