These are software programs that are designed to spread from one computer to another and interfere with the computers’ operations. A virus might corrupt data or could erase everything on a hard drive. Users can unknowingly spread viruses via emails with attachments that contain viruses. Viruses can be disguised as attachments of funny images, greeting cards, or in audio and video file.

Warning: do not open attachments from unknown sources and be careful in opening cute and funny attached files even from known sources, since this is one of the frequent means by which viruses infect computers.