I'm currently using a HP Pavilion dv4-1433us laptop.
The problem I'm having is this:
When I have my 'Default Device' (under Sounds >> Playback) set to Independent Dual Headphones, I get perfect sound from Headphones / Exterior speakers, but the second I disconnect all exterior sound devices, my built in speakers do not play any sound.
When I have my 'Default Device' set to Speakers and Dual Headphones, I only get sound from my built in speakers, even when I have headphones plugged in.
I did not used to have this issue, the built in speakers used to play perfectly, and the headphones would play the second I connected them. I believe this started after I downloaded a patch for IDT High Definition Audio CODEC. I'm not that knowledgeable on computers so I haven't figured out how to fix this.