If you are still having a problem installing SP2 you are entitled to Microsoft Support at no charge:
Microsoft Security Product Support Policy
Technical support is available from Microsoft Product Support
Services at 1-866-PC SAFETY (1-866-727-2338). There is no charge for support calls associated with security updates.
International customers can get support from their local Microsoft
subsidiaries. Phone numbers for international support can be found
Microsoft Security Bulletin - Summary for August, 2006http://www.net-security.org/advisory.php?id=6606
You can contact them at the phone number above or alternately you can go to the Windows/Microsoft Update page and click on "Get help and support" on the left side of the page.