If you install Microsoft Windows Security Update program for "Windows XP," you might have trouble opening streaming video files in RealPlayer and other programs. Below, please find instructions on how to set up Windows Firewall so that you may install Windows Update and Windows XP Service Pack 2.
1. Right-click on "My Network Places" in the Start Menu, and select "Properties"

2.When the above screen is displayed, right-click on "Local Area Connection", and select "properties."

3. Once the Local Area Connection screen is displayed as above, click on the "Advanced" tab, and then click on the "Settings" button.

4. Next, select the "Authentication" tab, and check the "Real One Player" or "Real Player" checkbox.
5. Click the "OK" button to complete the setup.