Malwarebytes is ace, always run a scan every week or two just to be sure. I don't think I've ever had anything show up though since I started using MSE though.
Oh I did I had to fix an infected pc so I plugged hard drive in to mine and the virus infected on to mine
MSE Avira Avast none of those 3 detected or could remove the trojan but malwarebytes did.
How did you connect the hard drive? by usb?