This is the way I found mine, which is rather circuitous:
In Administrator mode, click on Computer on your Windows menu, then select "C" drive (I have nearly all my FS2004 stored on a larger, spare drive but Windows registers some aspects of the program on the primary C drive).
Click on "Users" and look for a file with your name on it (in my case, Neil) which will appear to be padlocked. Operating in Administrator mode will allow you to open the file.
Look inside for a file called AppData, open it and click on a file called "Roaming". Inside Roaming you should find a file labeled Microsoft and the FS9 file inside it. Inside the FS9 file you should find the FS9 CFG file.
Hope this helps.
N.