Uninstalling SP2 after it hoses your windoze box

If you are prompted to type an administrator password, do so. If you do not know the administrator password, press ENTER. (Typically, the password is blank.)...Note The Spuninstal.txt file appears. As the file scrolls down, you will see errors and files being copied. This is normal behavior...After you restart, the system may lock up with a black screen. (Your mouse will work.) In this case, restart again by turning the computer off and then back on.
http://support.microsoft.com/