Windows Defender helps protect your computer from spyware and some other potentially unwanted software, but it will not protect against viruses. In other words, Windows Defender only protects against a subset of known malicious software but Microsoft Security Essentials protects against ALL known malicious software.

Which is better Microsoft Security Essentials or Windows Defender?

Microsoft introduced Security Essentials to cover the gap left open by Windows Defender. … MSE defends against malware like viruses and worms, Trojans, rootkits, spyware and others. Installing Security Essentials disables Defender, if present, as part of its install procedure.

Do I need Windows Defender and Microsoft Security Essentials?

A: No but if you are running Microsoft Security Essentials, you do not need to run Windows Defender. Microsoft Security Essentials is designed to disable Windows Defender in order to manage the PC’s real-time protection, including anti-virus, rootkits, Trojans and spyware.