:moved: from bug reporting to Help / support.
Just do as they said, use the toolbox that ships with your FH2 install to clear your cache. If you can't figure out how to do that you can manually clear it. There should be a cache folder for BF2 / FH2 somewhere in your My Documents folder. Delete the FH2 files in here and you should be just fine.
This problem is caused when you don't exit the game properl, the custom graphic shaders that FH2 uses aren't properly restored. WHen you launch FH2 it will temporarily swap some shader files, which are swapped back for the BF2 shaders when you exit the game. If the game isn't closed propely this will cause the shader problem with the graphical effects you are experiencing.