device driver, should the updated driver produce undesirable results. A copy protection system known as Windows Product Activation was introduced with Windows XP and its server counterpart, Windows Server 2003. All Windows licenses must be tied to a unique ID generated using information from the computer hardware, transmitted either via the internet or a telephone hotline. If Windows is not activated within 30 days of installation, the OS will cease to function until it is activated. Windows also periodically verifies the hardware to check for changes. If significant hardware changes are detected, the activation is voided, and Windows must be re-activated. Networking and internet functionality Windows XP was originally bundled with Internet Explorer 6, Outlook Express 6, Windows Messenger, and MSN Explorer. New networking features were also added, including Internet Connection Firewall, Internet Connection Sharing integration with UPnP, NAT traversal APIs, Quality of Service features, IPv6 and Teredo tunneling, Background Intelligent Transfer Service, extended fax features, network bridging, peer to peer networking, support for most DSL modems, IEEE 802.11 (Wi-Fi) connections with auto configuration and roaming, TAPI 3.1, and networking over FireWire. Remote Assistance and Remote Desktop were also added, which allow users to connect to a computer running Windows XP from across a network or the Internet and access their applications, files, printers, and devices or request help. Improvements were also made to IntelliMirror features such as Offline Files, Roaming user profiles and Folder redirection. Backwards compatibility To enable running software that targets or locks out specific versions of Windows, "Compatibility mode" was added. The feature allows pretending a selected earlier version of Windows to software, starting at Windows 95. While this ability was first introduced in Windows 2000 Service Pack 2, it had to be activated through the "register server" and was only available to administrator users, whereas Windows XP has it activated out of the box and also grants it to regular users. Other features Improved application compatibility and shims compared to Windows 2000. DirectX 8.1, upgradeable to DirectX 9.0c. A number of new features in Windows Explorer including task panes, thumbnails, and the option to view photos as a slideshow. Improved imaging features such as Windows Picture and Fax Viewer. Faster start-up, (because of improved Prefetch functions) logon, logoff, hibernation, and application launch sequences. Numerous improvements to increase the system reliability such as improved System Restore, Automated System Recovery, and driver reliability improvements through Device Driver