As promised during Microsoft's keynote at CES, the company today released the public beta of Windows 7. The ISO image gives users a largely feature-complete version of the next-generation operating system but sets the software to expire on August 1st. Microsoft warns that the software isn't officially supported and that downloads will be limited to the first 2.5 million who start the download.

While the software developer hasn't indicated running out of the early downloads, its download servers as of press time have been rendered slow or inoperable by the initial traffic.

Windows 7 is considered a relatively minor upgrade to Vista but has been anticipated since its public debut due to a focus on both a reworked interface as well as direct solutions to problems from Vista. The software hinges on a new taskbar that merges active apps and shortcuts and which lets users "peek" at different windows or run certain apps' commands from their taskbar icons. It should also run more quickly overall than Vista, reduce the number of intrusive notifications and simplify tasks such as wireless networking.

The test version is known to be an attempt to soften user apprehension about Windows, which with Vista has led PC makers to arrange repeated extensions of XP sales and Microsoft to launch its $300 million advertising campaign to promote the Windows brand.