Cn3D macromolecular structure viewer
Downloading Cn3D for Windows
  Download the Cn3D 4.3.1 installer here:

Close all internet browsers and then double-click on the .exe file.

The installer should automatically configure the common web browsers to launch Cn3D from NCBI web pages. If for some reason this does not work, see the instructions for manually configuring your browser.

The previous version, Cn3D 4.3, also continues to be available:
Revised 23 July 2015