The urban-legend of "viruses in hard disk residue" is an old and familiar one.
And who knows, it might be (or might have been) an issue in the grand old days of Windows, when everybody's grandmother was routinely running all-powerful "Administrator" accounts and
the Windows environment itself was a whole lot simpler.
Today, and certainly in Linux, it's an urban legend.
I have no doubt that the purveyors of "anti-virus" (sic...)
software have fanned the flames of legends like these at every opportunity, because anything that makes their
seem appealing, is "a good thing" to them. But the fact is, a computer is just a machine. It is not powerful enough
to be "infected by a virus," however intuitively appealing that human-notion might be to us.