Unable to install - Previous version installed.

I cannot install CDGSX8. The installation routine seems to go along fine, but at the end I get a message that says, "The installation was not completed. Your system has not been modified. To complete the installation at another time, please run the setup again. You cannot install this product because another version is already installed. To install this product, you must first uninstall the existing version. Click finish to quit the Setup."

No installation shows up in control panel. is there a way to clean up my registry to eliminate any previous installations?

I am running Windows 8.1 64-bit. I must have previously installed a trial version, but no previous install shows up in control panel. On my first attempt with live chat, I was told to reboot and try again. That did not work. On my second attempt with live chat, the agent asked me to send a screen shot of the error message (even though an exact transcript was provided), I attempted to paste an image file into the chat window and chat crashed. 

Is anyone aware of a method of cleaning up my registry to eliminate any previous installs?

Hard to believe in this day and age that the installation routine does not ask if I want to delete previous installations and then do it for me.