I've just installed Debian on a new Z61M. During boot there are messages about ALSA being recognized but RealPlayer9 fails with the message:

"Cannot open the audio device. Another application may be using it."

There is no other application. I cannot see any /dev/audio file.

This is kernel 2.6.18-4 (Debian stock kernel).

The audio device, from lspci, is:
Audio device: Intel Corporation 82801G (ICH7 Family) High Definition Audio Controller (rev 02)

Google shows one source which says that this should work out of the box with ALSA snd-hda-intel. I do not know how to set this up; I've installed various Alsa pacakages but cannot see this item.

Any suggestions gratefully received.

Try running "lsmod" in a terminal window. Look at the output and see if you see "snd-hda-intel" listed. If not, then you may need to load the module using modprobe.

I do have this module loaded. And alsaconf says that the device has been properly configured, but still it doesn't do anything.

Well, there are two possibilities. Either the module you need has already been compiled into the kernel or it was built as a module. If it was built into the kernel, then you wouldn't need to do anything. In fact, if you tried to load it into the kernel using modprobe, you'd get an error. All of the above said, normally, most distributions come with kernels that don't have a lot of drivers built into the kernel (as it makes the kernel image bigger). So, I would try this at a prompt:

$modprobe snd-hda-intel

and see what happens. Do another 'lsmod' to check and make sure it did load the module. If the modprobe above gives you an error, post it here and maybe we can figure out the next step.

ETA: Small correction made.

I get:

snd_hda_intel 17332 0
snd_hda_codec 137856 1 snd_hda_intel

Does this look correct?

Was that the output of lsmod after you explicitly did the modprobe or before? Either way, it's good, because it means the driver is loaded for your sound card. The only other thing you need to ensure is that all of the ALSA drivers are also loaded. They would be prefixed with "snd" as well. Unfortunately, I've built the drivers into my kernel (so they don't show up when I do lsmod), but you can basically figure out what should be loaded by visiting

http://alsa-project.org/

and locating your sound card. The instructions will tell you what ALSA modules you need. I will admit to this: I had major problems with the bundled ALSA modules with several different distributions. Those problems were solved when I removed all of the ALSA packages that came with my distro and downloaded the latest drivers from the ALSA website and built them myself. Your mileage may vary.

Something seems to be wrong. Following a suggestion elsewhere I tried speaker-test, which showed:
ithaca:~:$ ALSA lib confmisc.c:670snd_func_card_driver) cannot find card '0'
bash: syntax error near unexpected token `('
ithaca:~:$ ALSA lib conf.c:3500_snd_config_evaluate) function snd_func_card_driver returned error:
No such device

Well for anyone who's been following this thread (and thanks for all those who offered help), here is the end of the saga.

I tried Ubuntu and sound worked! As an added bonus, I could configure the wireless connection too. So Ubuntu it will have to be.