I have got the same problem here.
I downloaded the Thingworx Trial Edition Installer, attempted to install it, but i got an error message that i have to install Docker community edition. So I closed the installation, and set up the latest version of Docker, then I tried to install Thingworx again and it immediately returned with an error message:
"There has been an error. Please uninstall the old ThingWorx Trial Edition installation.".
In 'Programs and Features' there aren't any Thingworx programs that I could uninstall.
I have also tried to delete the Trial Edition Installer and download it again, but it returns with the same error message.