Desktop 4 requires .Net Framework 4.5 and Visual C++ 2013 to run. If one or both are not present it will try to download them and thus will need internet access.
Windows 8 already includes them, thus you should be able to install Desktop 4 to Windows 8 without an internet connection.
Windows 7 does not include them by default, thus if you wish to install Desktop 4 onto Windows 7 and have not already done so you'll need to download and install the following:
- Microsoft .Net Framework 4.5 - http://www.microsoft.com/en-
- Microsoft Visual C++ 2013 Redistributable (vcredist_x64.exe) - http://www.microsoft.com/en-
If you download and install these components for Windows 7, you should be able to install Desktop 4 without internet access.