These incidents have been happening for several years now, but recently, the occurrence has stepped up and more and more people are finding themselves the victims of computer protection scams.
The most common one out there, is someone calling from "Microsoft" or "Windows" support. They will tell you that your computer is sending out error messages or that it has been infected with malware or virus. At this point, any well informed user will realize that Microsoft will NEVER call anyone to help them with any computer problems (Microsoft isn't this proactive (sadly)) and you should just hang up. The next thing they will say is that they would like to take control of your computer and "show"you the error, completely disregarding any virus or malware that they have mentioned earlier. In reality, they just run a built-in function and force stop it after they finish setting up the "error". At this point, they will use your browser and take you to a website that will provide a fix for this error by paying, then downloading some stuff. However, this download is nothing more than a free anti-virus (reputable but out-dated) and a bunch a crap (usually bad) that is installed onto your computer that does nothing or opens it up to future threats.
There are several things you can do to protect yourself here.
Option 1: Hang up. Don't talk to them, don't interact with them, pretend there was no one at the other end of the call.
Option 2: Waste their time. Pretend to be an idiot about computers and do your best to stall them as long as possible. The longer they have to wait for you, the less likely someone else will fall for this scam. Time is money for them.
Option 3: Screw them, threaten them, call them names, insult them, do whatever you want to degrade them. I admit, they are only doing their job, but they are willingly going along with a scam artist so it doesn't really help their case.
A newer, but much more scary scam is a pop up that automatically comes up on your computer. The pop-up will do one of a few things.
1) It will disable everything on your computer except that one screen. It will tell you that your computer is infect, may have recovered from a sudden shut-down, or something that will make you wonder "What the heck is going on?!"
2) It will appear in a window and it will claim it is scanning your computer. It will automatically find several infections and and another prompt will follow.
3) It will appear to be a message from the manufacturer that the computer is sending an error or infected by something.
Then after one of those three, it will prompt you to do one of two things.
1) Call a provided number to a call center to help resolve the problem. The call itself will be toll-free to avoid any suspicion. Afterwards, the operator will ask to take full control of your computer. From there, they will direct you to an "Error" (It doesn't really exist) and tell you that you will need to download something to fix it. To download it, you will need to pay them some money, amounts vary.
2) Prompt you to download the anti-whatever it is called to remove the problem. To download it, you must buy it.
These downloads are usually crap and can be anything from junk files to further harmful stuff.
This type of scam is harder to deal with because it may disable various functions on your computer that will prevent you from doing what you need to do to get rid of it. At this point, you will have one of two options.
1) Try to get help from the real manufacturer. This usually doesn't work too well and you'll end up paying just as much if not more and you will get little to no information from them over the phone. (Sony is an exception since they have physical stores, but the staff there will not be trained computer specialists and will be just as helpless as if you were calling them on the phone).
2) Take it to a third-party computer specialist and have them inspect, diagnose, and repair it. Yes, you will still pay for it, but this will be a brick and mortar store that will have real people who have real training that you can interact with in real time in person.
To condense this entire wall of text, if anything pops up on your computer claiming that your computer has issues and can fix them for you, or if someone calls you claiming your computer has problems and will try to help you fix them, its a scam.