To perform an initial security assessment of your PC, I suggest you run the Microsoft Baseline Security Analyzer (MBSA). MBSA will report any missing Service Packs, Update Rollups and Security Updates. By clicking on Result Details in the report, you’ll be able to identify the updates needed to protect your computer. The MBSA report will also provide links to view the Microsoft Security Bulletin for more information as well as links to the Download Page. But to install any missing updates, I suggest you use the Windows Update website to install the latest Service Packs and Security Updates.
Download Miscrosoft Baseline Security Analyzer (MBSA)