Can I go to the restore point before installing the critical fixes?
You may be able to - click here - "...Installing an update by using Automatic Updates or installing an update directly by using Windows Update causes System Restore to create a restore point..."
These links may be helpful too - System Restore FAQs, How-to Guide & T'shooting - click here. How to configure and use Automatic Updates in Windows XP - click here. Good luck, G