Hackers claiming to represent Microsoft are using phishing attacks to dupe UK residential and business PC users into paying for fake anti-malware software and services.
The cyber criminals, claiming to represent a Microsoft partner company, E-Pro Solutions, contact users by phone, claiming Microsoft passed on the user's telephone number, supplied during the Windows registration process.
They claim the user has been the victim of a malware attack and Microsoft has asked E-Pro Solutions to contact the user to remedy the problem.
The hackers then direct the user to a directory showing a number of error messages, which they say demonstrates evidence of malware infection.
The user is instructed to go to a website from which the cyber criminals gain remote access to the user's PC.
After taking control of the user's computer, the fraudsters then demand payment to remove purported malware infections.
Stuart Aston, chief security adviser at Microsoft UK, said: "We are aware of scams involving people claiming to be from Microsoft and needing remote access to consumers PCs. We would like to remind users of Microsoft software that the company does not keep track of consumers that purchase their software and does not directly contact consumers for any reason whatsoever.
"Do not to trust any caller claiming to be from Microsoft and needing access to your home PC."
Anyone wishing to report a similar crime can contact the Home Office's National Fraud authority on 0300 1232040.