'If you perform a -rearm at the end of each 30-day period, you end up with 120 days of full, unfettered Windows 7 use, without having to supply an activation key.' 'You can run the -rearm trick a total of three times,' said Leonard. During days 28 and 29, the pop-up displays every four hours, while on Day 30, it appears hourly.īut by invoking the 'slmgr -rearm' command at a Windows 7 command prompt, users can reset the time-until-activation to 30 days, said Woody Leonard, a contributing editor to Windows Secrets and the author of several computer books, including Windows Vista All-in-One Desk Reference for Dummies.

For example, on days four through 27, a pop-up asks the user to activate once each day. As the grace period shrinks, however, increasingly-frequent messages appear on the screen. During the 30-day grace period, Windows 7 operates as if it has been activated. 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.

Windows 7 activation key