Q:? How can I change Product key in Visa/ 7 Operating systems.
Ans: To Change a Product Key in Vista/ 7 OS Follow these simple steps.
1. Click on Start Menu
2. Click on Control Panel
3. Click on System
4. In the bottom where it says Product ID next to that you will find a link which says Change product key, click on that.

Alternatively.
1. Click on Start menu.
2. right click on My Computer and select Properties.
3. In the bottom where it says Product ID next to that you will find a link which says Change product key, click on that.