Don't trust removable devices
USB drives and CDs are convenient ways to move information from one machine to another, but they also can transfer malicious software to your computer if one of those files is malware-infected.
"Most users think (malware) is only on websites and email, but it can also be hidden in downloadable files, photos and videos. Once these infected files are saved to a USB drive or CD, then the removable device also becomes infected," Stevens says. "From there, once the removable device is infected, then any computer that hosts the USB drive or disc will also carry the malware."
To protect yourself, make sure you're running updated anti-virus software on your computer.