user has administrative privileges, mostly for convenience. Because of this, any program the user runs has unrestricted access to the system. As with other operating systems, Windows users are able to follow the principle of least privilege and use non-administrator accounts. Alternatively, they can reduce the privileges of specific vulnerable Internet-facing processes, such as Internet Explorer. Since Windows Vista is, by default, a computer administrator that runs everything under limited user privileges, when a program requires administrative privileges, a User Account Control pop-up will prompt the user to allow or deny the action. This improves on the design used by previous versions of Windows. Spyware is also known as tracking software. Remedies and prevention As the spyware threat has evolved, a number of techniques have emerged to counteract it. These include programs designed to remove or block spyware, as well as various user practices which reduce the chance of getting spyware on a system. Nonetheless, spyware remains a costly problem. When a large number of pieces of spyware have infected a Windows computer, the only remedy may involve backing up user data, and fully reinstalling the operating system. For instance, some spyware cannot be completely removed by Symantec, Microsoft, PC Tools. Anti-spyware programs Many programmers and some commercial firms have released products designed to remove or block spyware. Programs such as PC Tools' Spyware Doctor, Lavasoft's Ad-Aware SE and Patrick Kolla's Spybot - Search & Destroy rapidly gained popularity as tools to remove, and in some cases intercept, spyware programs. On December, 2004, Microsoft acquired the GIANT AntiSpyware software, rebranding it as Microsoft AntiSpyware (Beta 1) and releasing it as a free download for Genuine Windows XP and Windows 2003 users. In November, 2005, it was renamed Windows Defender. Major anti-virus firms such as Symantec, PC Tools, McAfee and Sophos have also added anti-spyware features to their existing anti-virus products. Early on, anti-virus firms expressed reluctance to add anti-spyware functions, citing lawsuits brought by spyware authors against the authors of web sites and programs which described their products as "spyware". However, recent versions of these major firms home and business anti-virus products do include anti-spyware functions, albeit treated differently from viruses. Symantec Anti-Virus, for instance, categorizes spyware programs as "extended threats" and now offers real-time protection against these threats. How anti-spyware software works Anti-spyware programs can combat spyware in two ways: They can provide real-time protection in a manner similar