You can activate windows either online or by phone. To activate online you need an Internet connection. Activating by phone requires interacting with an automated phone system.
To activate Windows on your computer:
1. Start button.
2. Click Computer.
3. Click Properties.
4. Click "Click here to activate Windows now". If you are prompted for an administrator password or confirmation, type the password or provide confirmation.
5. You can then select the method you want to use to activate.
Note: To activate XP manually, you can also, at the command prompt, type
oobe/msoobe /a
then follow the on-screen instructions.
To change the product key:
1. Begin by opening the Registry Editor and navigating to
HKEY_LOCAL_MACHINE\Software\Microsoft\WindowsNT\Current Version\WPAEvents
2. In the right pane, right-click the ODBETimer binary value and select Modify. Change at least one character of this value to either a number from 0 to 9 or to a letter from A to F.
3. Click OK and close the Registry Editor. This renders the current product key invalid and deactivates Windows.
4. Now you can reactivate Windows using your new product key. Click Start --> Run and enter the command:
%systemroot%\system32\oobe\msoobe /a
For Vista and Windows 7:
1. Right Click on My Computer and Select Properties.
2. Wait a second for windows activation details to get populated.
3. Click on Change Product key link after your Windows activation details are populated.
4. Enter New Product Key and click on next to activate your windows.
