Microsoft Corp is getting ready to unveil a long-anticipated free anti-virus service for personal computers that will compete with products sold by Symantec Corp and McAfee Inc.

A Microsoft spokesman said on Wednesday that the world’s biggest software maker is testing an early version of the product with its own employees. Microsoft would “soon” make a trial version, or product beta, available via its website, he added, but declined to provide a specific date.

Microsoft has said it will provide protection from several types of malicious software including viruses, spyware, rootkits and trojans.