So I plug in my headphones last night...
 

and the sound from my speakers gets muted, as it should. But then, I don't get any sound from my headphones. Uh oh. Now, when I unplug my headphones from the pc, I can't get any sound.
I've triple checked every volume control, etc... but no luck. I know there is some mechanism by which your speakers get "muted" when you plug headphones in, and this appears to be permanently tripped, although without being able to get sound from the headphone jack.

I also tried plugging the speakers into the headphone jack, but still no sound.

Any ideas?

Re: So I plug in my headphones last night...
 

New sound card? Some more info would be helpful: laptop or desktop? onboard sound or sound card? etc.

Re: So I plug in my headphones last night...
 

Here are some more specs. It's an HP desktop...

- HP Media Ctr m7360y CTO Desktop
- Microsoft(R) Windows(R) XP Media Center Edition
- Dual NTSC TV Tuner with PVR and FM Tuner
- 256MB DDR ATI Radeon X 1600XT, TV-Out and DVI
- Sound Blaster Audigy 4, 24-bit ADVANCED HD Audio

Is it common to fry your soundcard by plugging a headphone jack in?

RESULTS!!!
 

So, I solved my own problem...

After drilling though every possiblity and using the useless windows troubleshooting program, I did the good ole SYSTEM RESTORE - back to the day before I lost my sound.

Worked like a charm.

Re: RESULTS!!!
 

So corrupted drivers?%