Stopping laptop speakers from playing alongside headphones

I recently bought a new Acer Aspire V 13. Having problems listening to headphones because the inbuilt laptop speakers keep playing when I plug in headphones, and I want to be quiet. I have Realtek HD Audio installed, but there is no headphone option, under playback devices I only have speaker. I saw another entry on superuser which circled a folder on the Realtek Audio HD manager, which should be located next to the "analog input, back panel" icon on the right, but no such folder exists for me. The audio does play though the headphones, but also the speakers, and I wish to have only the headph

Question by Dave on Super User, licensed CC BY-SA. We show a short excerpt and link to the original thread as credit.