Harry and Martha talked about it over the dinner table. Everybody sat up and took notice when Microsoft accidentally distributed a virus with one of their software releases. Yes, but consciousness was raised, along with the stock of companies producing virus detection software. Don't turn your computer on. While that seems extreme, keep in mind that the only way to guarantee that nothing goes wrong is to do nothing - ever.
Risks exist in every worthwhile endeavor.
Know the risks and reduce or avoid the worst of them. So turn your computer on and be careful what you put in it. If not, you have to check it yourself. Ask your vendor to check that next time you buy a computer with software already on it. Never load software from a floppy disk onto your system without checking it first.