Navigate to X:\...\AIM\Sounds (X being the drive it's installed on). You see all the sounds you normally hear. Replace these sounds with the sounds you want, making sure that the new sounds have the exact same names: for instance, if instead of the door slamming you'd like a nuclear bomb exploding, take the audio file of the bomb (ensuring it's a .wav) and rename it to "doorslam.wav" and replace the original "doorslam.wav."
That should do the trick.