This is true. But, on the other hand, if you say to someone, for an hours worth of work, and you charge $70 minimum charge to work on their PC, most people will pay that to get back to where they were before they were infested, rather than have a whole new Windows install with all that goes along with that.
Sometimes being professional is knowing WHEN to toss in the towel, quit applying band-aids and recommend major surgery... and maybe eat the hours you have already put in trying to resurrect a lost cause and just charge for the re-format/re-install.