Imagine you’re surfing the web looking for an entertaining video to watch while you’re waiting for the kettle to whistle or a phone call or maybe to flip your laundry over to the dryer.

You pull up your browser and type in YouTube’s URL.

Suddenly, instead of the homepage you’re expecting, your browser loads a bright blue screen that says “your computer is infected—call Microsoft tech support immediately at this toll-free number.”  It may even say that if you don’t call within a certain amount of time, your hard drive will be destroyed.  Maybe there’s a pop-up window directing you to contact tech support complete with the Windows and Microsoft logos.

This is the gateway to a classic tech support scam.  And it starts as soon as you dial the number listed on your warning screen.

But for as threatening as that warning is what you’re looking at is simply a web page like any other.

In panic, many users don’t think to look at the address bar to notice they’ve accidentally mistyped http://www.youtube.com, leading them to a page created to catch traffic from millions of users flocking to a popular site and typing the URL incorrectly.

Your computer isn’t infected.  You can navigate away from the page at any time.

But many users, fearing they could lose their (likely not-backed-up) data in the next five minutes, fall for the trap and call the number.

There are many different flavors of the tech support scam, but the goal is usually to get remote access to your computer, fabricate evidence of a critical issue, and eventually get you to hand over your credit card number in exchange for “fixing” the problem.

Here is a great walkthrough of how a typical tech support scam works (warning: this video contains some profanity):

If you’re lucky, the scammer will only charge your card for the value of the “protection plan” they discussed with you prior to payment.  If not, the scammer could charge your card for any amount, sell your card number to other scammers online, steal bank and personal information from your computer, or irreparably destroy your entire machine out of sheer maliciousness.

A particularly angering feature of this scam is how much it relies on a user’s unfamiliarity with their own systems to function.  The “evidence” the scammer presents to prove the need for purchasing his “tech support services” is pure nonsense—he’s merely walking the user through a series of normal command prompts and system processes a very casual computer user might not recognize, totally lying to the user about what they’re looking at to scare them.

Though seniors aren’t the only targets of this scam (more Millennials fall prey to tech support scams than any other age group), they do tend to lose far more money overall to tech support scammers.  For many, the financial damages are devastating.  One large loss like this can completely change a retiree’s life.

Stay skeptical about warning pop-ups and sites you may come across while surfing.  Always check the URL in the address bar to make sure you’ve navigated to the correct place, and always click the back button, try navigating to another page, or try closing and reopening your browser before you panic—just because your browser may say your computer is locked doesn’t mean it is.

Never call a random tech support number some web page or pop-up gave you unsolicited.  If you suspect your computer has been infected with malware, the best thing to do is call a reputable local professional.

To put yourself at ease, consider investing in a good antivirus program so you can regularly scan your computer yourself for any unwanted activity.

EMPLOYEES AT MICROSOFT, DELL, SYMANTEC, MCAFEE, HEWLETT-PACKARD, OR APPLE WILL NEVER CONTACT YOU TO ALERT YOU ABOUT COMPUTER PROBLEMS. Many of these tech scammers and their pages will try to tell you they’re from Microsoft or some other reputable software company.  They’re not. These companies do not keep track of your devices’ health and will not contact like this you to warn you about problems.  Anyone telling you that is lying.  The only thing that will monitor your device and alert you in the event of infection is your firewall and your antivirus software.

With a fairly basic knowledge of their computer’s operating system, many victims of this scam may have been able to recognize some extremely obvious falsehoods the scammer probably told while trying to show “evidence” of an infection.  If you aren’t totally confident in your computer literacy, taking a few computing classes could go a long way in protecting you from these scammers. Check your local senior center, community college, or check out one of the many online computer courses available for seniors.

AND PLEASE, PLEASE, PLEASE, PLEASE BACK UP YOUR DATA REGULARLY.