For previous versions of Microsoft Windows, users can download updates from the Windows Update website, using Internet Explorer.
Windows 95 and Windows NT 4 were retroactively given the ability to access the Windows Update website, and download updates designed for those operating systems, starting with the release of versions of Internet Explorer 4 for those operating systems.
The initial focus of Windows Update was on free add-ons and new technologies for Windows; security fixes for Outlook Express, Internet Explorer and other applications appeared later, as did access to beta versions of upcoming Microsoft software, most notably Internet Explorer 5.
Fixes to Windows 98 to resolve the Year 2000 problem were distributed using Windows Update in December 1998.
), a service offered by Microsoft, provides updates for Windows components.
It can be replaced with Microsoft Update, an expanded version of the service which provides for other Microsoft software as well, such as Microsoft Office, Windows Live Essentials and Microsoft Expression Studio.
Windows Update clients normally download updates over an Internet connection, although Microsoft makes provision for installing updates on computers without an Internet connection and a range of alternative methods and programs also exist to install updates. Security updates or critical updates protect against vulnerabilities to malware and security exploits.Other updates correct errors unrelated to security, or enhance functionality.Microsoft routinely releases security updates on the second Tuesday of each month (Patch Tuesday), but can provide them whenever a new update is urgently required to prevent a newly discovered or prevalent exploit targeting Windows users.System administrators can configure Windows Update to install critical updates automatically so long as the computer has an Internet mobile connection, without the user needing to install them manually, or even be aware that an update is required.Windows Vista and later provide a Control Panel to configure update settings and check for updates.The Windows Update Control Panel also has the function of downloading Windows Ultimate Extras, optional software for Windows Vista Ultimate Edition.