I love Hitman Pro, it's like a superhero of malware removal. The problem is, it's the kind of thing that I use on a given machine perhaps once every six months. If I've been to a client and used it previously, then I have to buy it. I'm perfectly willing to pay money for it, but I need something that I can use ocasionally on 50 or so different machines.
I kind of want to ask if there's a way to scrub the memory of it ever having been used from the registry, but I doubt anyone would answer that question.
If there's another uitility that can do the same thing entirely for free, I haven't found it.