The company said that the offer, which will start in October, provides basic anti-malware protection for smaller firms that may lack a dedicated IT department and do not need centralised management tools or a more extensive policy.
"It is very easy to get, and very simple to use. The software requires no registration, trials or renewals, and is available for download directly from Microsoft."
However, Microsoft recommends companies seeking advanced protection to upgrade to a more comprehensive package.
Small firms should consider moving to Windows 7 for improved performance and reliability, the company said, while those wanting to manage security and enforce policies centrally should look to Microsoft's Forefront security platform.
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