Vista - Odd sound problem

Hi there.

I have an odd problem i have never heard of before.

When i start up my new Notebook (which runs Windows Vista Home Premium w/SP1), i have no audio.
None whatsoever, even the Vista sound when you first see the logo after the core system has loaded doesn't make a noise.

Now, it remains like this, no matter how long i mess with the system setting or whatever else. It also doesn't give me any audio when i plug-in earphones.

Now, recently, i accidently hit the button on my notebook that will make it enter the power-save mode. So, after it had shut its parts down, i pressed a key to have it come back from hibernation, and guess what, the sound worked.

I have reconstructed this multiple times now, and it has always worked.
i.e., i'll start the Notebook and start playing some music. Nothing will sound. Then, i hibernate the PC, press a key, and the moment i see the login screen again, i hear sound.

Any idea what this is about?

It's a ASUS N50V notebook.

Thanks a lot in advance.