As you use your computer and browse the web, you may occasionally run into infection warnings that appear to be legitimate. These anti-malware warning messages—appropriately called “scareware”—are designed to force you into installing fake anti-malware programs that are actually malware in disguise. While scareware can be, well, scary, let’s explore how to tell if a virus warning is real. 3 Most Common Fake Virus Warnings While fake virus alerts could theoretically crop up in any manner, history has shown that three types frequently appear.