Buttons jumping on the screen???

Hello newbie here,

I am currently using the following button for a continue action and I would like to change it when I start redesign my project.

However when I simply move the object to another part of the screen or change the image it jumps around and I can't click on it even when the sound clip has stopped. I didn't change anything in the timing, just the picture and position.

How can I stop this from occurring? I have multiple slides and I would like to change all my buttons eventually. Thanks