A free online virus scan is pretty much what it sounds like: an online-based, free scan for viruses and other malware. This kind of virus scan differs from your traditional virus scanning program because all the work is done on a server on the internet.
Every online virus scan site does this a little differently. Some let you upload a file for scanning, others check websites for links that contain malware, and still others install browser add-ons or other small programs that scan your entire computer but do the behind-the-scenes work online.
Free online virus scanners are good option just for an extra layer of precaution. Regardless of why you're using one, each of the free online virus scan services listed below are completely free!