Did you purchase a Computer/Laptop with a pirated Windows 7 copy or with activated windows copy and want to change Windows 7 product key with a valid product key.You can either install the Operating System fresh with the new key or you can use the current operating system but just change the key with legal and valid key. Follow the below steps to change the existing key.
1.Click Start and Select Control Panel
2.Click System and Security
4. Click Change Product Key
5. Enter the new product key and follow the wizard for activation and you will be set with the new key.
There are other options to change the key from command window.Click Start and type CMD.Right click CMD application and Select Run as Administrator and in the command window type the command slmgr.vbs -ipk <type your product key here> by using they key and press enter and to activate this ley enter the following command slmgr.vbs -ato and the system will be activated with the new key.