Before buying the game I wanted to try out the demo but having issues getting it to run.

I downloaded the Windows demo, extracted it and seeing one file called "FPVFreerider_demo.exe" and a directory called "FPVFreerider_demo_Data". When I double click on FPVFreerider_demo.exe, the menu screen opens but nothing is clickable, it's all frozen. Anyone else having the same problem?

I'm running Windows 7 and graphics card driver (NVIDIA) is up-to-date, no log file is created under the FPVFreerider_Data folder.

Haven't heard of that issue before. You could try running the simulator in a window and see if that makes any difference. You run it in a window by adding command line parameters to the exe file, try this:

-screen-fullscreen 0 -screen-width 640 -screen-height 400