India-based Comantra is said to have cold-called computer users in the UK, Australia, Canada and elsewhere, claiming to offer assistance in cleaning up virus infections.
The calls used scare tactics to talk users into opening the Event Viewer on Windows, where a seemingly dangerous list of errors would be seen. This "evidence" was used to trick innocent users into believing they had a malware infection, and for Comantra to gain the users' confidence.
Duped users would then give permission for the support company to have remote access to their PC, and hand over their credit card details for a "fix".
Security firm Sophos says that internet users have been complaining about Comantra's activities for over 18 months, and it has taken a long time for Microsoft to take action.
Comantra's website still retains the Gold Certified Partner logo, although their details have been removed from Microsoft's database of approved partners.