When you turn on automatic updating, most updates will download and install without you having to lift a finger. But sometimes Windows Update will need your input during an installation. In this case, you'll see an alert in the notification area at the far right of the taskbar—be sure to click it. If you don't respond to a Windows Update alert, your PC might end up missing an important download.
We recommend that you use automatic updating—but if you choose not to, be sure to check for updates at least once a week.