Compare Norton Internet Security & Windows Defenderby Michael Butler
Both Norton Internet Security and Windows Defender can help protect your computer from threats caused by malicious software. Since the two programs have some of the same functions, they do not always work well when both are installed. The programs were designed for similar, but ultimately different purposes, and should not be seen as competitor products. Microsoft Security Essentials is closer to Norton Internet Security.
Windows Defender protects against one particular type of malicious software: spyware, which usually monitors your computing activites. Norton Internet Security protects against spyware and also protects against other threats such as viruses and Trojan Horses.
Since Windows Defender only protects against one type of threat, you will need to have additional antivirus software installed. Norton Internet Security was designed as an all-inclusive program to protect against almost any threat and does not require other software be installed.
Windows Defender is a free service pre-installed on Windows computers since the introduction of Windows Vista and is available for download for some older Windows operating systems. Norton Internet Security requires users to maintain a subscription for the program to continue working. As of September 23, 2010, the subscription cost was $69.99 for one year.