How do I get sounds to be played back through my earphones?

I would like to know how I can get all of the sounds on my HP Compaq laptop to be played back through my earphones and not the built-in speakers.
Windows Media Player for instance works fine when I start it up after plugging in the earphones, but apps like Mozilla Fire Fox uses the HP built-in speakers.

This is what the sound mixer for the built-in speakers look like when I've got the earphones plugged in:


And the earphones:




How do I get the other apps on the built-in speakers' mixer to be played by the earphones?

that's what i do...

also when i use skype, i use headphones as a default communication device, and speakers as a default device, so i can listen to music with speakers, and talk using the headphones.

I tried that, but the problem is that it doesn't set the headphones as the default device then, it still has the built-in speakers as the defaults.

mmm, then i don't know. just disable the built-in speakers temporary until you find a solution,

Okay, thanks for trying to help anyway. :)