And sometimes you can tell you have a virus just by looking. A weird image appears on the screen. Or music starts playing for no reason.
The Computer Virus Catalog is a compilation of some of the deadliest computer viruses in history.
The catalog is the brainchild of curator Bas van de Poel, a Dutch designer who's worked on advertising campaigns for Converse and Lego, among others.
"It's a personal art project that arose from my fascination for computer viruses," he told Business Insider in an email. "I've always been interested in the dark side of computing. I specifically wanted to do something with computer viruses when I found out that the Melissa virus is named after the author's favorite exotic dancer."
Van de Poel says he got in touch with artists whose works he likes, and asked them to make illustrations for him. "The viruses were selected based on their back stories and in some cases the visual effects they produce," he says.
Each picture is accompanied by a paragraph explaining what the virus does to your computer.