The Windows Registry contains multiple sections where modification of key values allows software to be executed automatically when the operating system boots. Spyware can exploit this design to circumvent attempts at removal. The spyware typically will link itself from each location in the registry that allows execution. Once running, the spyware will periodically check if any of these links are removed. If so, they will be automatically restored. This ensures that the spyware will execute when the operating system is booted, even if some (or most) of the registry links are removed. Overview Spyware is mostly classified into four types: adware, system monitors, tracking including web tracking, and trojans; examples of other notorious types include digital rights management capabilities that "phone home", keyloggers, rootkits, and web beacons. These four categories are not mutually exclusive and they have similar tactics in attacking networks and devices. The main goal is to install, hack into the network, avoid being detected, and safely remove themselves from the network. Spyware is mostly used for the stealing information and storing Internet users' movements on the Web and serving up pop-up ads to Internet users. Whenever spyware is used for malicious purposes, its presence is typically hidden from the user and can be difficult to detect. Some spyware, such as keyloggers, may be installed by the owner of a shared, corporate, or public computer intentionally in order to monitor users. While the term spyware suggests software that monitors a user's computing, the functions of spyware can extend beyond simple monitoring. Spyware can collect almost any type of data, including personal information like internet surfing habits, user logins, and bank or credit account information. Spyware can also interfere with a user's control of a computer by installing additional software or redirecting web browsers. Some spyware can change computer settings, which can result in slow Internet connection speeds, un-authorized changes in browser settings, or changes to software settings. Sometimes, spyware is included along with genuine software, and may come from a malicious website or may have been added to the intentional functionality of genuine software (see the paragraph about Facebook, below). In response to the emergence of spyware, a small industry has sprung up dealing in anti-spyware software. Running anti-spyware software has become a widely recognized element of computer security practices, especially for computers running Microsoft Windows. A number of jurisdictions have passed anti-spyware laws, which usually target any