Visual C# Express is free, but you need to register the product to be able to use it permanently. You need to obtain a key from Microsoft to activate your copy of Visual C# Express. Note that this key will be given to you for free after following the steps in this lesson.
Open Visual C# Express and on the Menu Bar, go to Help > Register Product.
You will be presented with a window asking for a Registration Key. Click "Obtain a registration key online" to begin the process of obtaining the key. An internet connection is required for the following process.
You will be taken to a page where you will be asked to log in your Windows Live ID. If you already have a Windows Live ID account, then you can sign in. If you currently don't have an account, you need to sign up for a new one by clicking the "Sign up now" button.
After signing in, you will be presented with a form that asks for certain details such as your name, email, country, and occupation. You will also answer some surveys regarding your interest on certain fields of .NET programming and how you intend to use Visual C# Express. Click "Continue" after completing the required fields. You may be required to verify your email so check your inbox for the verification email. You will see a link that you need to click in order to verify the email. After email verification, click the "Continue" button again. Wait for your registration key to pop up in your browser.
Copy the registration key and go back to Visual C# Express. Paste the key to the text box in the Registration Window and then click "Register Now". That's it, you can now use Visual C# Express permanently.