The PC version of this game is not available anymore because the official developers are also not in the business which means that no place to obtain the software exists on the web. If you have a phone, then you are in luck since the 3D Frog Frenzy is available for downloading from Android and iOS stores.
Here is the Archive.ORG version of the original software from where you can acquire the ISO: https://archive.org/details/3D-frog-frenzy
To run it in newer versions of Windows, DosBOX or VirtualBox need to be installed. One emulates older applications while the other allows you to install Windows XP or any other version to run it.
Note: For VirtualBox, original Windows XP version is needed.