Problem with default fs2004 737-400

Hello all!

Dont know if this is the right thread for this question
but i hope someone can help me with this problem.

I have been testing some avionics suits for my 737 project.I used the
default fs2004 737-400 for all my flying.
After finishing testing one program i tried the next...and for some reason
i changed the aircraft "cfg" and "air" file.Cause the suite came with
a specific aircraftmodel.

Now i have found the avionics program that i will go with
but since i played around with the files the simulator have
been acting strange...
So i uninstalled fs2004,deleted all files and installed it again.
Ran fs just to check if the 737 had reapeard in the
aircraft selection...and yes,there it was.

Life was good for a minute or two before i installed hardwaredrivers
for my cpflight mcp...
Ran fs again and like before both the 737 and 747 was missing
in aircraft selection

Dont understand why fs acting so strange even if
i reinstalled it?

Have a nice one people//lenne