The sound problem is long standing one, and a variety of solutions have been suggested for the 727. You might want to search that section. I don't know if they will work for the 737, but you might want to try.

In your Captain Sim folder in your FSX directory, you'll find a 737 folder, and inside it is a sound config file. Change the two entries near the top to from "1" to "0" like so:

SoundOffWhenSimIsSlew=0
SoundOffWhenSimIsPaused=0

Also, you might try putting msvcr71.dll into your FSX folder. If your computer has it already somewhere else, don't move it; just copy it. If not (and mine didn't) you can find it online.

Like I said, these are not 737-specific fixes, but since they work for the 727, they might work for the 737. I can tell you my 737 has sounds with these two fixes.