It is possible to install the version 3.0 over a full Windows version 2.76 in the same directory or to install only the version 3.0.
Run the installer file skychart_3.xxxxx.exe
to install in your prefered directory (i.e. C:\Program Files\Ciel)
At any time you can start the version 3 with cdc.exe
or the version 2.76 with ciel.exe