According to a Microsoft IEBlog post, users of Windows XP SP3 who installed the IE8 Beta 1 pior to installing XP SP3 may actually find the browser being locked into their system without any chance to remove the browser without a full reinstallation of the operation system.
This scenario will be in place if you installed IE8 Beta 1 before installing Windows XP SP3 and you now are now choosing to install IE8 Beta 2 on top of Beta 1 - and ignore a window with a warning. Microsoft said that you will be able to install Internet Explorer 8 Beta2, but once installed, you will not be able to uninstall either IE8 or Windows XP SP3 later.
“If you chose to continue, Windows XP SP3 and IE8 Beta2 will become permanent. You will still be able to upgrade to later IE8 builds as they become available, but you won’t be able to uninstall them,” program manager Jane Maliouta wrote in her blog post.
To avoid being locked into SP3 and IE Beta 2 we strongly encourage you to follow these steps before installing Internet Explorer Beta 2 (Again this only applies if you installed SP3 after installing Beta 1 or the uninstall of Beta 1 is greyed out):
- Uninstall Windows XP SP3
- Uninstall IE8 Beta 1
- Re- install Windows XP SP3
- Install IE8 Beta2
For more information check out the IEBlog's guide "Upgrading To IE8".