I was scammed by computer virus

I opened my computer late at night and found a notice saying it was frozen and has been invaded by a Trojan virus, which had infected 1,000 or so of my files.

It warned me not to turn off my PC as this would wipe out many of my files.

A message told me that only by telephoning a displayed number would I be able to clear the virus.

On ringing it, I was put under considerable pressure to hand over my PC for about 45 minutes.

I was told the “service” would clear the virus but only on my purchasing a three-year contract for £149.99 of a software cleaning programme.

Stupidly I agreed and all my online banking details and many more confidential files were put at risk.

I first wrote to you about this several months ago.

You then advised me on how to get my money back.

SAM UNDERWOOD, WORCS You had already bought and installed malware protection but this different service wiped it out. You quickly realised this and reinstalled your old one.

You then built in alerts on your Santander bank account to prevent large sums being taken out without your knowledge. Its free text and emails alerts to keep track of payments can be set up online, by visiting a branch or calling 0800 9123 123.

You had been sold the unnecessary service by a third party and had paid by credit card. I suggested you ask your credit card company to invoke section 75 of the Consumer Credit Act. It agreed there had been misrepresentation and you have your money back. You are aged 84 and want to stop others being misled.

The National Cyber Security Centre advises that any unsolicited pop-ups or emails are treated with scepticism. Often viruses could be introduced by clicking on such links.

Make sure antivirus protection is enabled and up to date, and that software updates to benefit from the latest mechanisms for averting current threats.

Sam Underwood said he was caught out by a scam on his computer, costing him £ 150