I just came across this instruction in the troubleshooting part of Microsoft's main gaming website. Thought the tip might be helpful for some folks to also know:
Rebuild the configuration file
To rebuild the FS2004 configuration file, press and hold down CTRL+SHIFT as you start Flight Simulator 2004 and start a new flight. Continue to hold down CTRL+SHIFT until the game is in Cockpit view.
Note When you rebuild the configuration file, some of your settings may change.
BACK UP that original fs9.cfg file FIRST!
best,
.....................john

Intel i7 960 quad 3.2G LGA 1366, Asus P6X58D Premium, 750W Corsair, 6 gig 1600 DDR3, Spinpoint 1TB 720



Mind you, you would have to miss out the backing up bit.......and you would have to know the tip in the first place :-/ :-/......commoner 
"In theory, there is no difference between theory and practice. But, in practice, there is."