I'm afraid that another Oldie reader has fallen foul of the scam that purports to be a call from an anti-virus "centre" (whatever that is). This is what he told me:
"I was contacted today by people who said that my computer was the source of error messages they had been receiving and that they would have to blacklist it unless they scanned and restored it to a bug free state. After extensive discussion they persuaded me to pay £199.99 for a lifetime warranty on my Windows system. Have I been had?"
I'm afraid the news is not good; he has certainly been conned, and the £199.99 has achieved no more than enriching the crooks.
The Guardian has an article about this scam here and Microsoft themselves write about it here.
There is also useful advice on how to deal with the aftermath here.
I also suggested that he calls his credit card company and tell them what has happened and ask them to cancel the card, and refund the money, if possible.
Please remember - these calls are ALWAYS con tricks. I get three or four each week. Just put the phone down.