I downloaded a 737-200 from yeo design, everything works except aircraft sound? There is a sound file. ???

You say it has a sound file.
You probably mean it has a folder named "sound". If this folder is inside the aircraft folder it should stay there. If it is outside the aircraft folder you should copy all the files it contains into your FS2002\sound folder.

Secondly: if the sound folder is inside the aircraft folder, take a look at what is in it. Are there a lot of files in it, or just a sound.cfg?
In the first case, it should work.
If the latter is the case then open the sound.cfg in Wordpad. It wil read something like this:

[fltsim]
alias=B737_400\sound

what is behind the "=" is what matters. It should point to an existing  "sound" folder containing a complete soundset in it. In other words: the folder (in this example) B737_400 must be in your aircraft folder and it must contain a found folder with a lot of files in it (not just a sound.cfg).
If this is not the case you won't hear any sound or perhaps some default prop sounds. You should then change the line so it points to a correct sound folder and save the sound.cfg  Make a backup of it before you do this.

My guess is your plane is aliased to a sound folder that does not exist.

Please let me know if this makes any sense to you.

AJ

you're welcome
AJ

Hi Sunstrike.  Welcome to the Forums!  To add AI aircraft, you'll need to programs called TTools and AFCAD.  Both are very simple to use once you learn how and what you are doing and both are freeware.  TTools is what you use to assign AI aircraft and their routes, AFCAD is what you use to alter the airports in FS.  There is a forum here for both, I would suggest checking it out.  

just wanted to say thanks to pippin and terbert for the reply to my questions and a special thanks for the welcome to the forum. I have downloaded the tt tools and the other part of tt tools is that afcad? i have not yet decompiled. I want to make sure i have done it right before i start on this task. As you know im new to the forum and trying to learn the extra cool stuff that will enhance my flt sim.

thanks for all your help. Sunstrike!
ps. Im looking forward to meeting all the nice people in the forum and what it has to offer.