Click on Start > then right click on Computer and click on Properties
The System basic information page will open. At the bottom of it, under Windows Activation section, the remaining days from the grace period (activation period) is displayed
Click on the link XX days to activate. Activate Windows now (where XX is the remaining days)
The Windows Activation page will be displayed. Click on Activate Windows online now to start activating your Windows copy, or click onAsk me later to cancel the operation.
If you haven't a Product Key (use trial verison), then after few moments you will receive a confirmation that your Windows copy has been activated 180 days trial
Then you will finally receive a confirmation page that confirms that activation was successful. Enjoy your genuine copy of Windows.
If you went back to the system properties page, you will find that the remaining days link has been replaced with: Windows is activated
