There are two versions (that I know of) of these types of scams.
We will fix you computer scam
A virus gets installed on your computer. You are prompted by a pop up display that you computer may be infected and to ‘click here’ to complete a scan. After a ‘theoretical’ scan, you informed that problems and errors have been found and for a credit card payment of typically $70-$100 dollars, the problems – be it errors in your operating system or viruses – will be taken care of. You are then informed that you will have 1 year of continuing coverage.
You pay the money and the ‘error message’ goes away. You are happy. What you do not realize is that the true virus was the one that put up the message offering to do the scanning and repairing. The scammers then update the code to reactive a year later. Or, they will just auto bill your credit card anyway if it has not expired. Generally, these ‘paid to fix’ scams never fix anything and maybe even make the situation even worse by installing additional stuff on your computer.
One major operation that was doing this was recently identified operating out of one of the former USSR countries, where they had 100s of programmers writing the code and finding ways to install it on computers.
A friend of mine fell for this multiple years in a roll where his computer would lock up and he would be demanded to pay $69.99 to free it up. The first time it happened, he called me and I was able to clear it for him. Then he went back to the sames sites where he got infected the first time and it happened again because he refuses (to this day) to run any kind of virus software. When he called me the next time, I told him I would be there in about 30 minutes. He decided to just pay the ransom and got his computer back. The next year his credit card was billed automatically for the $69.99 fee. When he got the bank to reverse it, about 2 weeks later his computer locked up again and demanded payment. He paid it again with a different credit card. I found out months later.
Never let any one scan your computer unless you are starting the process. Earthlink.net, McAfee, Norton and others offer scanning services where you can go to their website and request the scan.
Tech on the phone
My brother in law actually got one of these calls. A person will call and claim to be with tech support from a major well known company. It could be someone like Microsoft, Dell Computer or Apple or it could be someone who claims to be from your internet access provider.
The caller will tell you that they need access to your computer to either fix some know problems or as a free courtesy check. Either way, once they get into your computer (generally by having you log into a website they control) they will either install virus software to capture passwords, use the computer as part of a bot net or lock you out of the computer and demand payment for access. Either way you are permanently screwed and will need to reformat your computer losing all data and programs – or buy a new and start over. Even if you pay the ransom, it is say to guess that you will never have a completely clean computer again anyway.
This again is best defended by never giving any information over the phone and never allowing anyone to access your computer unless you initiated the transaction.