Windows Vista Service Pack 2 (SP2) is an important update that includes support for new types of hardware and emerging hardware standards, and it also includes all the updates that have been released since SP1. You'll find information about the specific changes and improvements included in SP2 below. For more information about installing SP2, see Learn how to install Windows Vista Service Pack 2 (SP2).
Here are some of the improvements in SP2:
Program compatibility. Microsoft works to ensure that your programs work seamlessly on Windows Vista. We also work with our partners to improve the reliability and compatibility of non-Microsoft programs. So, SP2 includes previously released updates that are available to you when you use Windows Update, and it also includes new compatibility fixes for individual programs.
Hardware support. Among other improvements, SP2 provides you with additional support for Bluetooth wireless technology and improved performance for Wi‑Fi connections after the computer resumes from sleep mode. Additionally, you can now record data to Blu‑ray Disc media.
General operating system updates. SP2 includes Windows Search 4.0, which has improved indexing and searching capabilities. SP2 also includes fixes that can improve recording TV using Windows Media Center.
If you are an IT professional or an advanced user and want additional detailed information about SP2, you can find the release notes, the SP2 deployment guide, and other information at the Windows Vista Service Pack 2 Resources page on the Microsoft TechNet