A/V Headphones won't work

Ok, so as the title says my headphones won't work. I have a Crative SB live 5.1 sound card, and a 5.1 intergrated in the motherboard, but when I plug my headphones in the blue hole, no sound comes out. I have set the crative SB as the default soundcard.
Im not really sure if this belongs in this topic, but I hope someone of yo ucan help me.

 

I think you may have it plugged into the wrong spot, the spot where headphones go are the second hole from the right.

 

Second from right.
*counting the holes*
No, I've plugged it into the second from right.
But knowing me I could easily have plugged it into a wrong hole.

 

Is blue not line in, green is usally line out, and pink is microphone.

On 5.1, i think its brown and black for rear and sub channels. Thats if the soundcard has colour coding. (i'll most likely stand corrected on this as my sound card isn't colour coded.

 

So yo ureckon I should try the green one?
*tries it*
*gets permanent hear damage*

Hey, it works! Thanks for helping. I always tought it was the blue one.

 

Yeah, except it's more of a yellow for center/sub and black is rears.

 

Ok, as someone then poste here, I'd like to ask: What the heck is the blue one then for?

 

Blue one is for Line-In (not mic), for connecting external things that already have a powerd sound out (i.e. CD/mp3 player), or for things like the ATi AIW TV Tuner Crossbar (tis what I use mine for)