Microsoft has recently announced that it will offer free software in order to protect PCs from viruses or trojans, in a move that could pose new challenges for independent security software makers.

Microsoft’s security software is code-named Morro and it will probably be introduced during the second half of 2009 in an effort to persuade more PC users to secure their computers against spyware, viruses or other forms of malware. Use of antimalware software is far from universal, especially in emerging markets.

It seems that there are two reasons for which consumers supply for not protecting their PCs, including a concern that the anti-malware software will slow down their PCs. Another reason consists of the cost of the security software, which can run $75 for the programs plus two years of updates.

This was revealed by Amy Barzdukas, senior director of product management for the online services and Windows division at Microsoft. Morro will replace another security software program from Microsoft, Windows Live OneCare, a broader suite of software and services. OneCare costs consumers $49.95 a year and its retail sales will be discontinued on June 30, 2009. Although the product received only mixed reviews, it significantly shook up the security software market, resulting in generally lower prices.

Microsoft has also started selling its Forefront line of security software for businesses and told the media at its Microsoft Online launch on Monday that it plans to expands its lineup of hosted security services. However, the shift to a free security offering from Microsoft could be a problem for Symantec and other independent security companies that charge consumers for their products. Morro will be available as a stand-alone download and it will offer malware protection for Windows XP, Windows Vista and Windows 7 operating systems.