Windows XP and Windows Server 2003
Windows Vista, Windows 7, Windows Server 2008, and Windows Server 2008 R2
During the installation of the update, your computer is checked for compatibility issues that may arise from installing the update. If compatibility issues are detected, you are presented with one of the error codes that are listed in the "Symptoms" section. The detection of compatibility issues may indicate the presence of malware on your computer. You must determine whether your computer is infected and then remove any malware before the Windows update can be successfully installed on your computer.
Some antivirus programs are sold with annual subscriptions that can be renewed as necessary. However, many are also available for free. Microsoft offers Microsoft Security Essentials, a free antivirus program that you can download from the Microsoft Security Essentials website. You can also visit the Windows Security software providers website to find third-party antivirus software.