You also can also manually install critical Windows updates manually, using Microsoft's Windows Update website. You can go directly to the Microsoft Update site at update.microsoft.com or just follow these steps:
Click the Windows Start button and select All Programs > Windows Update.
You will now be connected to the Internet and be taken to the Windows Update website.
Follow the onscreen instructions to install the latest version of the website software on your PC and scan your computer.
When the scan is complete, you are shown a list of updates that are available for your PC.
Follow the onscreen instructions to installs specific updates.