There seems to be a trend in web based malware today, masquerading as what looks to be a valid anti-virus message to the untrained eye. Click on the message and your system is infected with nasty malware which demands what amounts to ransom to fix your system and who knows whether the fix really works. This is the second time I am dealing with a friend's computer being infected by such malware. Both masqueraded as anti-virus/anti-malware solutions requesting payment to clean up the machine. The Washington Post this week published an article on the subject of these extortion schemes and how this malware morphs its messages based on the anti-virus software you have installed on the machine. The latest malware on my friend's machine was called "Advanced XP Defender" (the first one was Internet Security 2010), because the last go around I had installed Microsoft Defender and Security Essentials.
This malware was particularly nasty because it changes some key administrator privileges in the system where you can't even run .exe applications and corrupts your current anti-virus installation, in my case Microsoft's Security Essentials. I could not even reinstall security essentials.
In the end the two things that worked where to follow these Microsoft instructions (down the page) and installing the Malwarebytes free scanner. I can't say enough good things about Malwarebytes, it installed when MS Security Essentials would not and once updated with the latest signatures it was able to fully clean the machine. I was then able to install MS Security Essentials.
I think that MS Security Essentials' Real Time scanner would have caught this piece of malware but it did not. My question now is whether the free MS Security Essentials works well and maybe it's time to pony up the $24.95 for Malwarebytes full version.