I’ve not heard of hitman, which unnerves me. What’s that, then?
Rootkits are evil. There’s worse now too, crap that lives in filter drivers and the like. Horrible stuff to get rid of.
Be careful of Combofix. It’s very effective in certain circumstances, and potentially catastrophic in others. I’d head the advice they give with it and seek ‘professional’ help rather than recommending it as a magic bullet. That’s what MBAM is for – once you’re run a MBAM scan, you’ve dented the infection (if not cleaned it) and you’ve got a logfile which someone with experience can use to progress the patient.
Modern malware isn’t like the viruses of old; it’s sneaky and pervasive, and getting rid is a black art. Doubly so when you don’t have direct access to the box.