Following the closure of the browser, the user should disconnect from the internet to prevent any potential data transmission. Subsequently, the computer should be booted into "Safe Mode" and a reputable antivirus program should be run to scan for any actual malware that might have slipped through. Clearing the browser’s cache and history is also essential, as these pop-ups often leave behind "cookies" or scripts designed to reload the warning.
But before you click anything or call the number on the screen, take a deep breath. In many cases, the pop-up itself is the actual threat. Is the Alert Real or a Scam? trojan virus detected pop up