I recently installed Freelancer and Disco mod on the clean installation, it laucnhes and has the splash screen, but after that it CTDs and gives error "APPCRASH" with Common.dll. Ive reinstalled many times from a clean installation. Wierd thing was it was working yesterday. Also the Crossfire mod works fine.
Try to delete "C:\Users\#yourusername#\AppData\Local" and "C:\Users\#yourusername#\Documents\My Games\Freelancer".
I had a similar problem when I started and that solved it if I remember right.
"Common sense is the best distributed commodity in the world, for every man is convinced that he is well supplied with it." René Descartes