.Net Framework 3.5 (includes .NET 2.0 and 3.0) error occurs while installing some applications like Corel Draw X6, Microsoft Visual Studio 2008 and other softwares in windows 8. Windows 8 says the user to connect to the internet and download and install .Net Framework 3.5 (includes .NET 2.0 and 3.0) but if you are still facing the same problem, I have a fix for it. But before trying this fix, make sure you have windows 8 installation DVD inserted in your optical drive or you have windows 8 installation disk copied in your system's hard disk.
Let's start:

• First of all, open Control Panel > Programs and Features and then click Turn Windows Features On or Off.
• Now windows features dialog box will appear. Enable .Net Framework 3.5 (includes .NET 2.0 and 3.0) by clicking the checkbox before it and click OK. It will download the required package from the internet and install it in your computer. Now the problem should be fixed, but if you are still seeing an error, then you can try the command prompt method to enable .Net Framework 3.5 (includes .NET 2.0 and 3.0) so just follow the next step.

• Now, open command prompt as administrator and type the following command:

• In the above code, E:\ is the source drive for windows 8 installer DVD. You must change it as per your system's status.

• Now press enter key and wait for the process to be completed.

• Now if you check the Windows Features dialog box, you will find that .Net Framework 3.5 (includes .NET 2.0 and 3.0) feature is checked and enabled.

• Now you can install your applications easily.