If you have 1 sound file playing on say frame 1, how do you get frame 2 to play
a different sound, without playing frame one's sound as well? Right now 'frame
2' is playing both sound files. If I use the commande 'stopAllSounds' the frame
2 sound file will not play either.

I have two buttons. Click the first button and a sound plays. Click the 2nd
button and another sound plays, along with the second second also playing at
the same time!!

Please help.

One way to try is this:

Add a new layer in frame 2. Move your frame 2 new sound there.

Back on the first layer, add a blank keyframe at frame 2. Put in the Frame 1
sound there (yes, put it there again!). Now, down in the Properties panel, go
to the Sync drop-down list and select "Stop".

I think this will work.