When you choose this, Windows Update won't even check with Microsoft to see if important security patches are available.Give me recommended updates the same way I receive important updates: This option gives Windows Update permission to treat patches that Microsoft "recommends" the same way as patches thought to be "critical" or "important," and download and install them as you've selected in the drop-down box.If you're not prompted to install a new version of i Tunes, you already have the latest version that your operating system can support.Some features or devices might require a newer version of i Tunes than your system supports.Letting Windows Update check, download, and automatically install updates is a very good way to make sure you're protected from being exploited by security issues after they're discovered.Yes, at least in Windows 8, 7, and Vista, you could compromise by making that critical "install" part up to you, but that's just one more thing you have to remember to do.Participating in the Check for updates but let me choose whether to download and install them: With this option, Windows Update will check for and notify you of available updates but you'll need to manually approve the download and installation of them.
Automatic (recommended): Choose this option to automatically download and install updates of all kind—both important security patches as well as not-as-important non-security updates, like feature improvements and minor bugs.
Notify to schedule restart: Choose this option to automatically download updates of all kind—security, and non-security.
Updates that don't require a restart will install right away but ones that do won't restart your computer without your permission.
Allow all users to install updates on this computer: Check this if you have other, non-administrator accounts on your computer that actually get used. However, even when unchecked, updates installed by an administrator will still get applied to those user accounts, they just won't be able to install them.
Give me updates for other Microsoft products when I update Windows: Check this option, which is a bit wordier in Windows 7 & Vista, if you own other Microsoft software and you want Windows Update to handle updating those as well.