If you try to install Microsoft Windows Vista or Microsoft Windows 7, you will have at least 30 days to evaluate the software. After this period, you have to activate the software. If you want to continue evaluating Windows, then there is the way to extend your trial period.
How to extend the Microsoft Windows evaluation period?
Just type the following code on the command prompt:
And this will give you another full 30 days to try the operating system.
There is also another way to extend the evaluation period, and it could give you a 1-year evaluation period.
1. Run regedit.exe and then go to HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsNTCurrentVersionSL or search for SoftwareProtectionPlatform.
2. In the text change SkipRearm value to 1.
3. You will be able to use slmgr -rearm for eight times.