Microsoft is set to release a fully supported version of its Windows Live OneCare offering, marking its entry into the security software market.

OneCare will be available for download today on Microsoft's site, a day earlier than expected. By tomorrow, the software is expected to be widely available in US retail stores, according to Samantha McManus, business strategy manager for Windows Live OneCare at Microsoft.

The software will begin shipping outside the US "within the next year", she said, declining to say which country would be the first to follow the US launch.

OneCare includes a firewall, an antivirus system and backup software, as well as Microsoft's Windows Defender antispyware technology, which is still in beta form. The product also handles routine maintenance tasks such as defragmenting the hard disk and cleaning up unused temporary files.

Microsoft's entry into the market has shaken things up for security vendors such as Symantec and McAfee, which are now scrambling to deliver products that have the same backup and PC tuning features as their new competitor.

Symantec expects to ship a OneCare competitor, code-named Genesis, by the end of the year. Yesterday, McAfee said it would deliver its own backup and security product, code-named Falcon, by September. A beta version of Falcon is expected within the "next few weeks", according to a McAfee spokesman.

With the release of the final version of OneCare, users can now get telephone support for the software. And Microsoft is now selling OneCare subscriptions under a novel, three-user, $49.95 (about £27)-per-year plan, which is designed to simplify things for home and small-business users.

The OneCare beta scheme, which has been running since November, will be phased out over the next few months, and beta users who want to continue to run OneCare will be compelled to purchase the product, McManus said.

However, a new beta scheme designed to test the upcoming Windows Vista version of the software will start up later in the year. Windows Vista is expected to ship in early 2007, and OneCare for Vista will be available around the same time, McManus said.

Security software is commonly distributed with new hardware or included with internet access services, but so far, Microsoft has said little about how it plans to distribute OneCare beyond retail and its site. "We're still pretty early with this service," McManus said. "We're definitely investigating a number of ways we could make this more broadly available."

Microsoft is also considering the idea of including an online backup service with OneCare, similar to that planned for Symantec's Genesis, McManus said. At present, OneCare can back up to external hard drives, CDs or DVDs.

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