a few weeks back, apparently on FB. I have Malwarebytes pro, which I really like, but it and my Avast. weren't catching the virus/trojan. I visited a couple of forums that recommended Housecalls that didn't catch it either. Finally I tried Superantispyware which zapped it and a few other pieces of malware that the previous programs were missing.
I'm only a few steps above being computer illiterate, but it seems different programs specialize in different areas.