Hello, this problem came up recently. I used to have my headphones listed under Audio Devices along with HDMI output and speakers.
Yesterday after shutting my laptop down and restarting it i saw that the headphone icon has disappeared. I do get sound if i plug in my headphones but it still shows it as speakers. The sound quality has decreased compared to before.
The following is my system
AMD Athlon Dual Core M300
ATI HD mobility Raedon 4200
Hope someone will take time out and reply . Thank you very much .
Try heading to the laptop manufacturer's support site and re-installing the sound card driver. It could be a system glitch of sorts that accidentally messed with the sound card driver, so reloading it could fix the issue. Let us know how it turns out.