Viewpoint requires the .NET Framework 3.5 which is not part of Windows. During the ViewPoint install, Windows will automatically try to download and install the missing components. In the event that Windows has been unable to install the .NET Framework 3.5, the most likely reason is that your internet connection is controlled by local domain management policies. Whatever specific network issue is causing the problem in your environment, Microsoft supports a method for installing the .NET Framework 3.5 that does not require an internet connection.
If you cannot download the .NET Framework 3.5 components from the Internet, you can enable the .NET Framework 3.5 using the Deployment Image Servicing and Management (DISM) command-line tool and specifying the installation media (ISO image or DVD) used to install Windows.
The two Microsoft page links below contain the detailed information needed to obtain the .NET Framework 3.5.
Basic Install Instructions
This link directs you to a page with the basic install instructions that should solve the problem.
Skip down to the troubleshooting section to find the instructions on using Deployment Image Servicing and Management (DISM) to do the install.
If this link does not work, you should be able to find the information with a Google search on the phrase: ‘Installing the .NET Framework 3.5 on Windows’
Microsoft .NET Framework 3.5 Deployment Considerations
This link directs you to a page where you can download a document containing an extended treatment of .NET Framework 3.5 deployment considerations.
If this link does not work, you should be able to find the information with a Google search on the phrase, ‘Microsoft .NET Framework 3.5 Deployment Considerations’.