[CentOS] Sound setup on ASUS laptop (Intel High Definition soundcard)

Hi,

I just got a brand-new ASUS laptop, a W6F light laptop. So far I managed 
to get everything to work (wireless, X, ...). The only thing that 
stubbornly refuses to work is the sound. Here's the sound card:

# lspci | grep -i audio
00:1b.0 Audio device: Intel Corporation 82801G (ICH7 Family) High 
Definition Audio Controller (rev 02)

I googled quite a bit for this. Some folks suggested to put an addition 
options line in /etc/modprobe.conf. Here are some of the suggestions:

options snd-hda-intel model=asus

... or:

options snd-hda-intel model=asus-laptop

... or:

options snd-hda-intel position_fix=1 model=asus

I tried all these (and duly rebooted after each attempt), but to no avail.

Usually, to test the sound, I open a terminal and try to play one of the 
test sounds in /usr/share/sounds/alsa with the command-line 'aplay'.

Anyone got that sound card to work? Any suggestions? I'm quite clueless.

Cheers,

Niki