Last time I checked, and it has been several months, Defender was rated almost the same as having no Virus Protection at all.. Has this changed at all because of the almost daily updates to it? Just curious.
Hmmm. Looks to be so:
AV-TEST - The Independent IT-Security Institute: Jan/Feb 2013
Then I wondered what the difference is between Defender and MSSE, both of which are from MS.
Does Microsoft Security Essentials replace Windows Defender and what - Microsoft Community :
MS Security Essentials is an antivirus with an antispyware component. Windows Defender has no antivirus component. MSSE replaces Windows Defender and gives you the antivirus protection you also need.
Now, that's a dated article, and MS now insists that Defender does protect against viruses along with other things:
Windows Defender and Windows SmartScreen are built into Windows 8 and Windows RT and help guard your PC against viruses, spyware, and other malicious software in real time.
Interestingly, MSSE doesn't seem to exist for Win8/RT when I searched MS' site. At this point, I'm not sure what the real difference is between those two besides platform availability. Anyway. The fact that Defender did find viruses for OP and probably some other people shows it kinda works, but in the Windows RT environment, it's not needed. I disable mine on RT to get those resources back, especially since I don't download every other app or side-load ARM-recompiled bits beyond PuTTY.
But still keep in mind that it's the ONLY option for Windows RT right now, so regular users should just leave it if they have a modicum of worry.