What are the Requirements for Installing SP3?
Make sure your computer is up-to-date with Windows Update and there is a minimum of 1.5 GB free disk space. It is recommended that you backup any critical data before installing SP3. For laptop computers, ensure that the laptop is connected to AC power prior to starting the installation.Customers who have installed the Internet Explorer 8.0 beta or who have not installed Service Pack 2 on their systems will NOT be offered Service Pack 3 through Windows Update or Automatic Updates. The service pack may still be downloaded and installed from the Microsoft website.