All Windows-based computers need a product key to activate the software. This is a security measure designed to stop software piracy and fraud. The Windows product key is printed on a sticky label attached to the side of desktop computers and the underside of laptop computers. If the print on the label has worn off or the label on your computer is missing, you can still find the product key for Windows 7 on your computer. To find the product key in the computer, you need to access the computer's properties information window. This displays the Windows 7 product key information in the "Windows Activation" settings.
Click the "Start" menu from the computer's desktop toolbar.
Right-click "Computer" from the "Start" menu.
Click "Properties" and find the Windows Activation heading at the bottom of the properties dialog box.
Find the "Product ID" label under the Windows Activation heading. The Windows 7 product key is the 20-digit alphanumeric code beside "Product ID." Copy the product key for future reference.
Don't click the "Update Product Key" link beside the product ID number unless you need to validate your Windows 7 installation or buy a new product key. This is usually only necessary if the operating system has stopped working because it's illegal, pirated software.