i got comparable system. but i dont shutdown any of programs when i installed it. it installed smoothly and works fine. both WIN XP, and WIN 7x64.

some folks says that MS NET FRAMEWORK can affect FSX, or MS VISUAL C++ which installed with OS by default, but i dont know if it true. You'll probably need some missing *.dll from that software for fix the sound, but gauges should work for sure.

my guess: something block aircraft from loading into FSX completely, so *.GAU files not loaded. or something block installation, so CS_B727-100\PANEL\ folder missing or incomplete.