The redesigned browser, Internet Explorer 10, made its debut last month when Microsoft released Windows 8, which makes dramatic changes to an operating system that has been powering PCs for decades.
Internet Explorer 10 initially is being introduced Tuesday to Windows 7 users in a "preview," or test, mode.
Although Microsoft is staking its future on Windows 8, far more PCs rely on Windows 7. Microsoft Corp. says more than 670 million Windows 7 licenses have been sold since its release in 2009. Windows 8 is unlikely to approach that level of usage until 2014 at the earliest, based on analyst forecasts.
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