Windows 7 will be available on new computers starting Oct. 22, according to Microsoft. That date puts Microsoft ahead of the year-end retail season; however, it largely misses the annual back-to-school sales window. Those who buy a Vista PC in the weeks preceding Oct. 22 may be eligible for a free upgrade to Windows 7 once it’s available, but details of that program remain unclear. Microsoft announced the final release date for its new OS Wednesday during a keynote address at Computex 2009 in Taipei, Taiwan.