quote:

INTRODUCTION
This update includes the following improvements:

• It extends the battery life for mobile devices.
  
• It improves the stability of portable computers and of desktop computers that use an uninterruptable power supply (UPS).
  
• It improves the reliability of Windows Vista when you open the menu of a startup application.
  
• It improves the stability of wireless network services.
  
• It shortens the startup time of Windows Vista by using a better timing structure.
  
• It shortens the recovery time after Windows Vista experiences a period of inactivity.
  
• It shortens the recovery time when you try to exit the Photos screen saver.
  
• It improves the stability of Windows PowerShell.

This update also resolves the following issues in Windows Vista:

• A compatibility issue that affects some third-party antivirus software applications.
  
• A reliability issue that occurs when a Windows Vista-based computer uses certain network driver configurations.

Known issue
Note This package has been updated to version 2. An issue was identified in which certain computers that have specific combinations of older AHCI USB chipsets and CD or DVD drives that use the SerialATA interconnection bus may not start after the installation of the original version of this package. Version 2 of this package has removed the fix that caused this problem. If you are using a computer that experienced this issue, you can restart the computer by using a bootable Windows Vista DVD and by selecting the Repair/System Recovery options. If your computer has already installed the original version of this update and has successfully restarted, you do not have to install version 2 of this update.
Download the update for Windows Vista x86-based versions (KB941649) package now.

Download the update for Windows Vista x64-based versions (KB941649) package now.