If you want to have the full-performance DSViewer to view files you create or download from other sources, see the information in the CHEM 350 website http://mason.gmu.edu/~sslayden/Chem350/manual/molmod.htm#viz
Because of its easy user interface and because of its enhanced features, I recommend using DSViewerLite as the external helper application for molecular viewing on the Web Supplement site. If you install DSViewerLite on your computer, you can launch it from a browser web page as an external viewer for either .PDB or .MOL files. Most of the files on this site are .MOL files but large protein files are in the .PDB format. The advantage of the MOL format is that it shows multiple bonds.
Do the following after installing DSViewerLite on your computer:
If you have Explorer:
-Open Explorer.
-Left-click the name of a molecule file. A window will open asking whether you want to open the file or save it.
-Choose to save the file in a convenient folder or the Desktop.
-Right-click on the saved file. Choose "Properties". On the General tab, find "Opens with" and click the "Change..." button.
-Browse to find DSViewerLite.
-The next time you left-click a molecule file name, the file should open in the application.
If you have Firefox:
-Open Firefox.
-Left-click on the name of a molecule file. A window will open asking whether you want to open the file or save it.
-Choose to open the file. From the Browse menu, choose DSViewerLite from the applications list. If these don't appear, choose "Other" and find one of them on the list of applications.
-If you want to view the molecules every time using your chosen application, check the box "Do this automatically...".
-You can change these options by going to Tools/Options/Applications on the Firefox menu bar.
The molecule will appear as a stick model when first viewing it in ViewerLite. Press (Control + D) in order to change the molecule display preferences. Select a style.