Eliasz Brzozka
Eliasz Brzozka voted up Walt O'Reagun's answer

Sure there's a way to prevent it ... Don't open any attachment, unless you are 100% positive it's safe. 

Our IT department had to "scrub" a virus from the hospital computers a few months ago, because somebody was reading their personal email at work and opened an attachment from an advertisement.  It took a week … Read more