After installing the Cortona VRML Client plugin, reboot and install the Cortona VRML-1 to VRML-2 converter.
You may have to choose "manual installation" of Cortona, which allows you to select the specific browser plug-in directory to contain the npCortona.dll plug-in.
Only the main mouse button is used by Cortona, and its action is determined by selecting a button along the left edge of the VRML window. Move the mouse over the button to discover its action - Fly, Examine, Plan, Pan, Turn or Roll the model by dragging the mouse. The buttons along the bottom are used to GoTo, Straighten, Restore or Fit the model. Probably you will want Examine and Turn with Fit. Right-click the window to select the "fastest" speed and other options.