Does Microsoft Security Essentials replace Windows Defender?
Yes. Windows Defender protects against adware and spyware, while MSE does all that and more (protection from viruses, rootkits, etc).
MSE will actually disable Windows Defender to manage your PC's realtime protection. Also, from the Security Essentials Wikipedia page:
Microsoft Security Essentials (MSE) (Previously codenamed Morro) is a free antivirus software created by Microsoft that provides protection against viruses, spyware, rootkits, and trojans for Windows XP, Vista, and 7.
MSE replaces Windows Live OneCare — a subscription antivirus service — and Windows Defender, which only protects users from adware and spyware.
What he says it true, Michael. He is telling the truth!– user9520Oct 2, 2009 at 4:18
It should be noted that in windows 8 and 8.1, Windows Defender has vastly improved towards the older windows versions and is basically a full malware protection. answers.microsoft.com/en-us/protect/forum/mse-protect_start/… for more info.– NzallJan 7, 2014 at 14:26
Windows Defender says it protects against viruses now.– JonathanJan 10, 2015 at 20:04
There's been an update. Windows Defender now replaces Microsoft Security Essentials in Windows 8 and 8.1
You seem to be missing my point. Don't worry about me. I will just reverse my vote.– RamhoundJan 16, 2015 at 20:52