Windows Defender is Microsoft's approach to the detection and removal of adware, spyware and malware. While is is not as robust as some of the other softwares on the market, this software is a must for every Windows XP based computer and has become an included package with Windows Vista.

One advantage the free Microsoft Windows Defender has over the competition is the ease of use. The first time the program is installed, it will ask to update the program and definitions, then scan the computer. Once this is complete, you won't see, hear, feel or otherwise be annoyed with the program. It sits quietly in the background and monitors the activity of your computer to help prevent any outbreaks or issues. If Windows Defender does detect any issues, it will promptly let you know.

Keep in mind that this software is not a replacement for an Anti-Virus software. You will still need to have something in place to detect Virus's.