How to Key in Product Key in Visual Studio

Your trial period has already expired. You now want to register the product after purchasing a license.

Solution 1:
1. Go to Control Panel via Add or Remove Programs
2. Look for Microsoft Visual Studio <YourVersion>. Right click, then click Uninstall/Change.
3. It will load the installation components. Just wait until you go to the Maintenance Page.
4. At the lowest part of the window, you will see the textboxes to key in the Product Key.

Solution 2:
Here's a much simpler solution. Hehe...

MSDN says, to upgrade from a trial edition of Visual Studio Professional, Premium, or Ultimate, the following simple steps are just what you need to do:

1. Start Visual Studio in Run as Administrator mode.
2. On the menu bar, choose Help, Register Product.
3. Specify the product key, and then choose the Next button.