I'm in IT, so I knew when I got the first call that it was a scam... especially when the guy told me my computer had 'called them' and told them it was infected. I fished for a little information, and then hung up. They started to call every single day, and I got more and more frustrated, finally telling them that if they didn't remove me from their list I would report them - and the calls escalated to several times per day (I had stopped answering). I had the number blocked, and they started calling again several weeks later using Skype, which can not be blocked with existing technology. On the day I received an even DOZEN calls (yes, 12 calls in a single day), I called the RCMP - but was told that nothing could be done because the calls originated outside of Canada. At the end of my rope, I purchased a whistle and started picking up the calls again... not speaking, just blowing the whistle into the phone.
The calls have stopped now, but I'm amazed at the persistence of these morons. I hope everyone here is aware that your computer isn't calling ANYONE and asking for help even if it IS infected with a virus, and that no reputable company will ever call you on the phone to suggest that you need to install stuff. Any critical security updates for software you already have will be pushed through automatically, and as long as you're smart about not visiting questionable sites, opening email attachments, and having an antivirus program installed, you will be fine.