Fake software, fake scan but the cost is real enough.
Millions of pounds are being made by online criminals encouraging computer users to download fake anti-virus software, internet security experts claim.
Symantec has identified 250 versions of "scareware".
Criminals can sometimes use it to get the victim's credit card details.
BBC News website readers have been recounting the difficulties they have faced with scareware.
Read the full story
COMPUTER USERS WHO HAVE BEEN AFFECTED
I have been tricked into buying fake anti-virus protection. There was a pop up saying my computer was infected and I needed to purchase software immediately. It looked identical to the legitimate Windows warning so I entered my credit card details and paid $39.95 (£20.00). I immediately got suspicious because the support line number was unrecognised and the email addresses they contacted me with were fake. I cancelled my credit card so they could no longer use it and I am just hoping I have no more problems and that they haven't taken over my computer.
Victoria, Pengam, Wales
I was hit by this scam on Facebook. When downloading a family recognition tool the "infection" prompt came up and it looked like and referenced the Windows Defender prompts I had become accustomed to. When the prompts turned to the question of paying for the updates (once it had already been downloaded) I cancelled the installation. Unfortunately since then it had already gleaned my Facebook login details which mirrored my hotmail login details. Both accounts were then used to contact people on my address or friends lists.
Paul Smith, Southampton
I have been done by these people and because they look so official it's very easy to fall for it. I was in the middle of writing my research thesis on a work computer which held all my data. Luckily, I realised fairly quickly and took it straight to a computer repair man. It took him three days to get it working back to normal and it was so scary because I thought I had lost a lot of data, not to mention money. I have now switched to a different kind of computer and have it loaded up with virus protection.
Catherine, Edinburgh, Scotland
I received an alert that told me to scan my computer. But the scan took only 20 seconds and it published a report of very dangerous spyware on my PC. When I searched for these files in the "system32" folder, they were not there! I became suspicious and deleted the program. But the programme came alive the next day. I restored my PC to the previous date and my PC was OK, and yes they did ask for credit card details to download software to eliminate the virus.
Len Wood, Sint Maarten, Netherlands Antilles
Just this weekend, I got blitzed by this Antivirus 2010. I didn't download anything, but that didn't stop it. My computer is fully patched and running antivirus software, but that didn't stop it. I am tech savvy, but even so it has taken me almost two days to wrestle control of my computer back. There needs to be an international effort to stop the perpetrators of these scams. Governments need to have agreed penalties for the criminals behind this. Law enforcement needs to be as aggressive against identity theft as they are against drugs.
John, Lund, Sweden
Just last week my computer screen lit up like a Christmas tree showing a Windows display of hard-disks and showed massive numbers of infections on my C: drive and advised me to buy something pronto. The supposedly infected computer was running Ubuntu Linux and therefore doesn't have a C: drive so it was easy to deduce that it didn't know anything and well worth staying clear.
Leigh Bowden, Stockport
We were hit by this scam. On realizing what happened I called the credit card company to report the scam and cancel the card. The bigger problem was with the computer. The malware destroyed windows files and kept popping up despite attempts to remove it. To fix the problem I had to reinstall Windows and reinstall my anti-virus software. In all my computer was out of action for about 10 days as I tried various abortive ways to fix the problem. I was lucky, I was able to save my data and eventually get the computer going again but it was extremely disruptive.
Brian Maturi, Detroit, USA
I was confronted with a pop up called "Security Tool" last week, when I clicked on the pop up it told me I should either "scan for virus" or "continue un-protected". Initially I scanned for viruses and it told me I had 39 malicious viruses in my computer. The option to remove them then took me to a page where I could pay for various levels of security and removal starting from around $60. The fact that it was in dollars was what made me first suspicious, up until then I thought this was genuine! Thankfully I did not pay the fee after asking some friends' advice. I then went on to Google to see if other people had this problem and I found lots of useful information. It's really frightening to think that people can take over your computer like that and risk you losing your personal photos, music etc., as well as possibly stealing your credit card details!
Emma, Edinburgh, Scotland
I have had a computer rendered useless by this scam. It will not let me open any program unless I download their program that costs £75. I'm not an idiot and had adequate protection but this got in on the back of either an email or a download. This will not allow you to open any program at all even security. I have lost a lot of work and photos, warn others.
Mike Power, London
ADVICE FROM THOSE IN INFORMATION TECHONOLOGY
I work for a technology company that has to deal with getting this "stuff" off of folks computers. It isn't easy. It sometimes requires a reinstall of the entire operating system (OS) and sometimes it means a loss of data. This is very nasty stuff. Like anything else in this realm, just think; if your OS already has virus protection why didn't it pick it up? This should warn you that you're about to download malware. Refrain from downloading anything that you didn't specifically ask for unless you're sure of the content i.e. Microsoft updates.
Allan Frazier, Milford Delaware USA
As a self-employed mobile PC repair man I am fixing more and more of these problems. It seems that in the last three years, but recently in the last 12 months the problems have really stepped up. Most can be easily removed with malware bytes but increasingly these rouge programmes are disabling the .exe files, blocking scanner updates and even corrupting the .exe. Combo fix is also pretty good combined with malware bytes but I have had to reinstall a pc from scratch to get around this issue. I've even seen one recently that had an mp3 warning that the PC was infected which played after the welcome screen!
Chris Williams, Bromley Kent
I work as a PC tech and system admin and I have been seeing this type of malware regularly for about three years now. I have to fix about one machine a week where the user has been infected or tricked into purchasing a dummy security application. They end up paying at least twice; once for the fake program and once to have it removed, and you would be very, very lucky to get away with not having your financial details stolen too. If you want security software visit a genuine, well-known vendor.
I repair computers for friends and this anti-virus scam is so unfair on normal PC users, I've had my work cut out lately once this stuff gets into a system it can be a real pain to remove. My advice is to be very careful what you click on to, and if you are unsure then just close your browser and start again.
Paul Howe, Ripon, North Yorkshire
I'm an IT technician. I have had to deal with this issue a number of times now. One of the scams is called PAV or "personal anti-virus" You can find it if you search for it. It slowly slows your computer down, weather you pay or not. The longer it's there the harder it is to get rid of, and it stops your ant-virus from working. The way to get rid of it if caught early is to download malware-bytes. This will clear it. If PAV has been on too long it stops anti-malware from working. Then you need to start using REG-Edit to try and clear it, then it's a long process.
Mark Partridge, Shropshire
Most people are already scared of their computer and even more scared of viruses. In my experience in IT support as soon as these pop-ups appear people panic. This is the online version of the guy who pretends to be the gas man and then dupes granny out of all her money. Very sad. Thankfully not all operating systems are susceptible to this issue. It's something to think about before buying a PC.
Paul Burland, Stansted, Essex
As a PC doctor, for mainly the home user, I have had the opportunity of cleaning out many a scareware software scam. Most of this software looks so real, is cleverly designed and stops the user from attempted to using other software diagnostics to clean it out. If a user has been unfortunate to have paid for such a scam then if a credit card has been used then ask them for a refund of your payment! As always my advice is to ensure your data is regularly backed up, preferably to an external hard drive, and don't rely on internet security tools in keeping the malware at bay. Ensure your browser includes some form of web rating technology so that when you PC 'door' is open via the web then your browsing will be safe.
PC Doctor Edward, Croxton
It is probably easy for me to say because I've been using computers since the Commodore PET days but you are in control of your machine, even if you have the slightest doubt about a website or pop-up or whatever, turn off your browser. If you can't do that break your connection, reset your machine or even turn it off and start again. Strangely enough lack of money helps in these situations. If I got a message directing me to a download which asks for £60, there's no way I would carry on even if it was genuine!
Don't get me wrong I've been caught out by viruses in the past, usually of the trojan variety. But if you're vigilant, have a good virus checker, your spyware detector is kept up-to-date, use trusted websites and tread carefully when using new websites you should be OK. It's a bit like developing a streetwise attitude, just keep your wits about you but enjoy yourself!
Guto T Evans, Cardigan, Wales