"The Initial Grace period of Windows Vista can be prolonged up to 120 days by simply entering the
slmgr.vbs –rearm command in the command prompt window. In this manner, users will be able to
extend the initial 30 days Windows Vista testing time frame up to three times. But at the end of 120 days of prolonged initial grace, users will have to activate the operating system as Windows Vista will automatically move into reduced functionality mode.
Microsoft considers this move perfectly legal and in accordance with the Windows Vista end user agreement. Furthermore, the Redmond Company also provides documentation on this option on the Vista Volume Activation 2.0 support website."
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