Thank you for your post.
I am unable to replicate the issue. This is what I did:
1. On a new Windows 10 Enterprise (64-bit) machine, I downloaded the trial from our web site and installed it.
2. I was then prompted to install Bonjour (which I did).
3. After completion, I launched FileMaker Pro 14 trial and I got the Welcome page.
4. I clicked the button "Try FileMaker Pro" in the bottom right corner, and I was able to continue on.
Assuming the installation did not fully complete, I would remove the FileMaker Pro folder, and reinstall again. If the issue still continues, see if you are able to install on another Windows 10 computer.