SettingsModifier:Win32/PossibleHostsFileHijack

Today I got a message from Windows Defender about SettingsModifier:Win32/PossibleHostsFileHijack while my computer was idle.

I only ever use this computer for gaming and use Firefox with Noscript and Adblock so I'm not quite sure how I could have gotten infected, I'm fairly paranoid when it comes to viruses :S.

When the message popped up I clicked the "perform action" button which I think repaired the file, should I have done that?
Regardless I went through the steps below to check if whatever modified it in the first place is still around.

I completed all the steps in this thread with no problems: http://forums.majorgeeks.com/showthread.php?t=35407

I am using Windows 7 Home 64 bit.
I then went through this http://forums.majorgeeks.com/showthread.php?t=139681.

I was able to download and run SUPERAntiSpyware without any problems and nothing was detected.
I already had Malwarebytes installed (not sure if this will affect anything). I ran it fine and nothing was detected.
I didn't run Combofix or Rootreal as I use a 64bit OS.

I was able to download and run MGtools without any problems and found nothing.

My normal anti-virus program is Avast, I scanned with that and still found nothing.

I've attached the logs just in case.

Could this be a false positive since nothing was detected? What else should I do?