Microsoft on Wednesday revealed plans to unveil a test version of its latest Windows computer operating software later this month. The US technology titan sent out invitations to a \"Windows Consumer Preview\" event to be held on February 29 at a hotel in Barcelona during a Mobile World Congress gathering in that city. Microsoft promised to release more information closer to the end of the month. The introduction of a test, or beta, version of Windows 8 to the public is expected to be accompanied by the opening of an \"app store\" stocked with mini-programs tailored for the next-generation operating system. In December, Microsoft began wooing developers for a February opening of its first Windows Store intended to feature third-party applications crafted for computers powered by the Redmond, Washington-based firm\'s software. It will take on Apple and Google in the booming market of fun, hip or functional programs built for smartphones, tablets and computers.