Vista - No Sound, tried almost everything, please help!

Ok so for a few days now my audio has not been working, I use it quite frequently with itunes and dvds etc but not ever very loudly. I've been on my laptop's website and have tried everything they've suggested except for system restore, and nothing has worked. I've made sure my computer is completely updated, I have downloaded the newest update of the audio driver from the website, and still no luck. In Device Manager it says everything is working, I have no error signs either. The mixer picks up the sounds when I test for it, I just can't hear it! It doesn't work with headphones either, although when I plug my headphones in and pull the socket in and out a little bit I can hear crackles in the headphones. Any ideas? Could really do with some help asap! Thanks

Unfortunately, I have had a similar experience, that has left me pretty mystified.

I have an XPS 720 from Dell. My sound driver is SigmaTel High Definition Audio CODEC.

Everything has been running fine, except for today. Last night I watched a movie, then set my computer to backup to an external hard disk while I slept. When I woke up, I wrote a few emails, then someone sent me a msg on gchat. It was kind of a loud beep, and that's the last time I recall the sound working. After that it wouldn't work.

The memory filled up because I had too many programs open, and I had to restart my computer. When I restarted, there was a blue screen error in startup, it mentioned something about IRQ.

When I play music or a video, there are no errors, and it appears to be working looking at the mixer or Sound control panel (shows sound levels changing, etc). Also, it is not the speakers, when I plug them into my laptop it works fine. After trying to uninstall and reinstall the drivers, enabling/re-enabling (both in Device manager and bios) I have had no luck. I have even tried to do a system restore to 2 days ago when it worked fine. Still no luck.

I do not have a sound card. I looked at the motherboard, and all the connections were there.

What could this possibly be? Could it be a hardware problem somehow? Or something else? I am completely mystified and at my wit's end, any help would be incredibly appreciated!

Thanks!
Christina

Additionally - here is the blue screen error I received when things first started going bad:

IRQL_NOT_LESS_OR_EQUAL

try plugging in headphones and see if u can still get sound. if u still get sound that rules out drivers. and youve probably tried this but go to your sound settings in control panel and ensure that its set to use your built in speakers. sometimes programs and plugging in outside speakers can change that...i no it did for mine lol

Hi. Do anyone know how i can get the sound back on ingame? The problem only conserns Call Of Duty: World at war.
No audio problems in other games.

check your audio settings to see if they reset to no volume when u start the game

Definitely "Memory". Now , if you hvae an integrated Sound card , you gotta throw off that Motherboard in the bin and procure a new one . If you have an additional Sound card ( PCI X) you have to buy a new Sound Card. Since you have reinstalled the drivers , the issue is beyond software scope.

dell support
You can fix the problem by opening your sound settings by right clicking the volume icon, click on playback devices, click on speakers and click on properties, go to the advanced tab at the top of that window, and change the sound quality to 16bit 48000Hz, apply and test, it will be working again.