Indeed herman. Wiping the HDD and starting again is the best (and sometimes quickest) way to deal with such things.
However...real world...customers...critical machine...no backups...licenses lost...complexity of existing build...how much willing to pay...etc.etc.
Please note I do not run a IT team in a corporation etc. I deal with customers that walk in off the street.
So no clone builds or structured processes. Oh I wish...