Microsoft is prepping to release a Windows 8 preview build during its Worldwide Partner Conference on July 11th, according WinRumors. Reportedly, the Redmond-based firm will “detail Windows 8 substantially,” during the conference, and it could present a second preview “building Windows 8″ video, which we hope will show off several of the OS’s new features. Microsoft first took the wraps off of its Windows 8 demo during the D9 conference in June, when Microsoft’s Steven Sinofsky discussed the Metro UI and other features that will apply to both PCs and tablets. So far we know that Windows 8 will include Internet Explorer 10, and will be able to run both desktop applications as well as HTML 5 and Java apps that are designed for tablet-sized devices. Microsoft’s current demo devices run on Intel processors, but there are reports the company is running tests on ARM chips as well. The Consumer Electronics Association also announced on Thursday that Microsoft’s CEO Steve Ballmer will give the opening keynote during the annual Consumer Electronics Show in January 2012 — and we suspect we’ll hear a lot more about the new OS at that time.