Report
Windows Defender is Microsoft's answer to the growing problem of spyware. In 2004, Microsoft purchased 'Giant AntiSpyware'. After some rebranding, Microsoft have released the final version of Windows Defender. Here is what Microsoft have to say:

'Windows Defender is a security technology that helps protect Windows you from spyware and other potentially unwanted software. Known spyware on your computer can be detected and removed. This helps reduce negative effects caused by spyware, including slow computer performance, annoying pop-up ads, unwanted changes to Internet settings, and unauthorized use of your private information. This enhanced protection improves Internet browsing safety by helping to guard the places where spyware can enter your computer. .'