Microsoft has ramped up the distribution of its free Security Essentials anti-virus and malware tool from 17 countries and eight languages to 74 countries and 25 languages in the five months since launch.
The software provides basic anti-virus protection to licensed users of the Windows operating system that automatically updates through the Windows update facility.
"We expect to be in up to 83 countries and 33 languages by the end of the first half of 2010," said
Theresa Burch, director, product management, Microsoft Security Essentials (MSE).
MSE is designed to avoid the common reasons for not installing security software such as cost, payment barriers, and impact on performance.
Although unwilling to disclose actual numbers, Burch said the total number of downloads of MSE is more than double Microsoft's estimates by this time.
More than a quarter (26%) of the downloads to date are in emerging countries, including Brazil which is one of the fastest adopters, because few security software suppliers provide free trials.
The practice of providing a free trial, followed by the purchase of an annual subscription does not work in Brazil where relatively few people have credit cards, said Burch.
This has made it relatively difficult for people in Brazil to get security software, but now MSE provides free lifetime security software without the complication of subscription renewals.
This means that the number of computers in Brazil protected by security software has increased by more than a million in the past five months.
Microsoft believes this is good news for the whole online community because vast numbers of computers that were previously vulnerable to exploitation are becoming protected for the first time.
The number of previously unprotected computers is likely to increase further still as Microsoft expands its distribution channels beyond the direct download facility provided at launch.
"Since December, PC makers (OEMs) have been able to download a kit to pre-install Security Essentials," said Burch.
This means OEMs who are not paid by big security software suppliers to pre-install free trial software are able to ship PCs with Security Essentials as a value-added service, she said.
Third-party support providers are also taking advantage of the pre-install kit to provide infected customers with a way of protecting their machines to prevent further infections, said Burch.
Another new and important distribution channel for Security Essentials, she said, is service providers such as online banking sites and online gaming sites.
"Service providers do not want infected machines connecting to their networks, but now have an option to block access to unprotected machines, while offering a link to free protection," said Burch.
At this stage, service providers can only display a link to download MSE from Microsoft.
"We are just starting to talk to online service providers, but plan to enable them to host the software on their own sites," said Burch.
Commercial security software suppliers claim they are not concerned by Microsoft's move because free software does not have the support that the more important business market requires.
But more than half of UK small and medium businesses which use security software rely on free products, a survey has revealed.