The best defense against viruses is to install software, which is specifically designed to detect viruses and protect your computer and files from harm.

The best defense against viruses is to install anti-virus software, which is specifically designed to detect viruses and protect your computer and files from harm. Anti-virus software is called also anti-malware software. It is a set of software programs installed on computers with the goal to prevent, to detect and remove viruses. Example for viruses are  worms, trojans, adware and many more.

He would most likely be employed by a gov. agency or homeowner because he has the required skills that have to be known to apply and get hired into those jobs.