What makes you think that you need to delete the preferences file? Is the application in your program files folder? Can you launch it from there? Is it giving you an error?
I found a solution for the Mac version where that was the solution. I though Window might be something similar. No, I was not able to launch it from the program files. I was only receiving the blue spinning wheel for about 5 seconds and then nothing would happen.
I actually just fixed it. For some reason .exe was running in the process in task manager. I ended the process and was then able to open Filmmaker successfully.
Thanks for the reply Mike.
When in doubt on windows, restart, usually fixes a lot of issues!