Activate Windows Vista without downloading any software

Preliminary experiment, check the activation expiry date with the command: slmgr -xpr
Launch Regedit.
Navigate to this path:
** HKLM\SOFTWARE \Microsoft\Windows NT\CurrentVersion\SL
Double-click Skip Rearm and change the value to 1.
Note: this registry hack does not make any sense on a machine which has already been activated!
Now remember to run the 30 day extension command: slmgr -rearm
Restart the machine. After it reboots, run slmgr -xpr and check the expiry date.
Check the registry setting Skip Rearm, slmgr resets the value to zero

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.

However, Microsoft has taken the flexibility it allows for the Windows Vista activation process one step further. In this respect, one overlooked command, also documented by Microsoft, is Skip Rearm.

"Skip Rearm specifies whether to run the Windows Software Licensing Rearm program. Rearming a computer restores the Windows system to the original licensing state. All licensing and registry data related to activation is either removed or reset. Any grace period timers are reset as well," revealed Microsoft.

Rearming is a procedure that is supported by all the editions of the Windows Vista operating system, according to Microsoft. Let's read between the lines for a minute. Via these two workarounds, users could postpone the activation of Windows Vista indefinitely. The combination of slmgr. vbs -rearm and Skip Rearm will continually prolong the Windows Vista initial grace period by 30 days and also perpetually restore the operating system to the original testing licensing state.