Before you install the latest version of the Microsoft Security Essentials virus and spyware definition updates, you must know: Whether Windows XP, Windows Vista, or Windows 7 is running in a 32-bit or a 64-bit operating environment.

How to download a Windows update manually. Windows XP Windows 7 Windows Vista. Windows Update can help you download updates. But if you want to manually download a certain program in the Windows Update list, such as a Service Pack or a specific security update, follow these steps.