Windows Vista KB941649

From Microsoft:

This update improves the compatibility, reliability, and stability of Windows Vista. 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.