Like its predecessor, Windows 7 can be used for up to 120 days without providing a product activation key, Microsoft confirmed Wednesday.

Although Microsoft generally touts a 30-day time limit for users to activate their copies of the company's operating system, a little-known command designed for corporate administrators can be used by anyone to "reset" the countdown up to three times.

Late yesterday, the Windows Secrets newsletter published step-by-step instructions on using a single-line command to add an additional 90 days to the stock 30-day grace period.

Microsoft allows users to install and run any version of Windows 7 for up to 30 days without requiring a product activation key, a 25-character alphanumeric string that proves the copy is legitimate. During the 30-day grace period, Windows 7 operates as if it has been activated. As the grace period shrinks, however, increasingly-frequent messages appear on the screen. For example, on days four through 27, a pop-up asks the user to activate once each day. During days 28 and 29, the pop-up displays every four hours, while on Day 30, it appears hourly.

More: http://infoworld.com/d/windows/windows-7-will-run-120-days-free-microsoft-confirms-323