I have a really weird problem, so thank you for any advice/help in advance. This may take awhile...so I'm sorry if this is a little longer than you guys hope for, I just don't want to miss any details

Specs: HP Pavilion dv5-1099nr Notebook PC
2 Intel Core 2 Duo T5800 Processors @ 2.00 GHz ea.
Windows Vista Home Premium
4.00GB RAM
320GB internal HD, 250GB external
NVIDIA GeForce 9600M GT Video
IDT High Definition Audio

I think that's it if you need anything else just ask!

Okay, now my problem...

My laptop speakers are Altec Lansing, not sure if that matters, but they produce no sound in normal operation. The headphones work flawlessly, but when I unplug them the speakers do not kick in and take over...I lose all sound. It gets even better, though, because if I mute my speakers, then unmute them I hear a split-second clip of audio...then all is quiet again. There's a pop, like a click, when I unmute and sound comes out, immediately after I unmute, but as soon as it started it goes away

So I go to my IDT Control Panel...here's where it gets even better. I notice my playback is set to "Speakers and Dual Independent Headphones." There's a picture of a set of headphones, and if I click either side of the headphones it's supposed to make a sound...it does, but I can't hear it unless I mute and unmute, which as I stated earlier only works for a split second. Well, if I'm looking at the IDT panel, and mute my speakers, then a picture of 2 floor speakers pops up, and all of this is with OR without headphones plugged in. Same thing, click on the left or right side to test sound and voila...nothing. Mute and unmute produce a minute sound...then nothing. Sigh.

One more thing. In my IDT Control there's also a picture representing my jacks...headphones (my laptop has 2 but only 1 is pictured), and microphone. If in operation then the picture is supposed to be enlarged, and in fact my headphone jack is ALWAYS enlarged...unless I switch playback WHILE I'm in HDMI mode. Still no sound, though...but ever faithful headphones ALWAYS work. Double sigh. The jacks are good...switches are fine, everything is soldered good, and everything looks peachy. I'm positive it's not the headphone jack switch and everything I've learned looks to me like a software issue.

Is it possible my settings are somehow reversed or screwed up in either BIOS, or the registry? I've chatted online with HP Support, I also called HP Support and had them override my computer while someone a million miles away toyed around on my desktop disabling deleting drivers, reinstalling drivers, running MS FixIt, and a few other things.

The last time my speakers worked perfectly I was watching a DVD. I remember having to leave so I shut my laptop lid...only to come home to a non working set of speakers. I was using Windows Media Center.

So there it is. PLEASE help, please this is driving me bananas. I restored, recovered, deleted and reinstalled drivers, even KLite codecs...nothing is working. Nothing. All system checks are okay and FixIt says nothing's wrong. Can someone suggest something I've yet to try? Thank you for your patience

Any advice? Bump...

i think the laptop is 'fooled' to think that the headphone is always plugged in hence there's no sound from the built-in altec speakers.

You just said exactly what I was thinking, and I can prove it with screenshots. Short story, the speakers work...it's not hardware related. For some reason my IDT program is sending all audio to my headphones whether they're plugged in or not. How can I fix this? Is there a way to erase not only the program and drivers associated with this program, but also every file ever created, or setting, by this program? I've uninstalled it, all audio controllers, and everything but everytime I restart my computer after doing all that it immediately reinstalls all drivers and the problem persists. It's like I can't undo what's been done and I don't even know what's been done lol.

Is there a way to fix this? Everything works hardware wise, nothing is broken, it's just my system "thinks" for whatever reason my headphones are plugged in and all audio is routed to my jacks. BTW the jacks are all good I've triple checked and checked again the switch isn't the problem and all connections are solid.

I'm seriously at wits end lol.

There is a switching mechanism on many computers where the headphone socket is located.... You plug in the headphones and the external speakers shut off... When you unplug them, the switch springs back... you might look for that switching mechanism using a srong light.

I've thought of that, checked each jack to compare any abnormalities using a pen light and a ready toothpick...didn't even need to use the toothpick but I even gently poked around in the jacks nonetheless. I'm about 99% sure it's not my jacks.

I noticed something more today, though, that's pretty interesting while poking around...

1. Sound is muted, I muted it.
2. I disabled every playback device (4 of them)
3. I enabled "Speakers and Dual Headphones" only.
4. (Observation) In both IDT Control Panel and Playback Device window "Independent Dual Headphones" are "not plugged in" and disabled.
5. (Observation) The graphic design on my IDT Control Panel representing my default playback device is of two floor speakers...I guess representing audio output to my built in speakers.
6. All I do is unmute sound.
7. (Observation) The graphic design on my IDT Control Panel switches to represent a pair of headphones...I guess representing audio output to a set of headphones.
8. (Observation) "Speakers and Dual Headphones" are still my default playback device in both IDT Control Panel and Playback Device window.
9. (Observation) IDT Control Panel has "Independent Dual Headphones" as "disabled" while my Playback Device window shows it as "Working"- rather than what was observed in step 4 above.
10. Headphones are not, and were not, plugged in. All I did was unmute my sound.

Last one, promise, lol...after all of that this is what I further noticed...

11. If I disable all playback devices, and select "Independent Dual Headphones" as my default, mute sound, and test sound then I hear the test coming out of my laptop speakers. Headphones either plugged in or not.

Thanks, guys, really for both patience and advice. I'm really really stumped and I feel like a complete noob because I'm usually more technologically capable but MAN this is lame. Thanks again, and please I'll consider anything. Is there a way I can change drivers or switch to something other than IDT? Will I have to replace my soundcard? I'm almost to that point.

this may be out of topic but here is my experience:

physical mechanism:
when you plug a small screwdriver / 3.5mm jack to it, the laptop speaker will mute, thus it detects the headphone / external speaker arrival. but, as you insert the small screwdriver further, the red laser light will lit, indicating that it kinda detect digital signal. finally when the screwdriver reach the end, red light stop lit and the sound will passed to analog speakers. this applies if your laptop has SPDIF output on the headphone jack.

driver mechanism:
common problem with the macbookpro 2009 models is that when users install windows XP and apple default driver provided in the laptop, the headphone jack will lit (red light) indicates that it's sending digital signal (optical) while the analog speaker and onboard speaker still works. driver update solves this.

have you tried completely remove the driver and update it?

I have the exact same problem. With Windows 7. I have no doubt at all that this is caused by the IDT driver. if I uninstall all IDT software from my laptop, the speakers will work. The sound isnt great but I guess that this is because the default driver has no enhancements.
To make this even more strange, the headphones do not work in the laptop when I have un-installed the IDT drivers. However they do work if I plug my headphones into my docking station.
I have tried contacting HP and their answer is to restore the laptop to factory defaults. I know this will not fix it. I have also tried contacting IDT but to no avail.

I know this is not helping but there seem to be a lot of people with the same issue