Hello:
Well, I just installed Slackware 9.0 on my Compaq Presario 700. Everything works fine, except for the sound. If I try playing a CD, or MP3, or MIDI, or anything, it will start playing, but no sound comes out of the speakers. I've tried chmod, even edited the Config file for the kernel, but still haven't got any sound out of my speakers.
I dont get any error messages.
The Compaq Presario 700 comes with a VIA VT86C686A [Apollo Super AC97/Audio] Chip, and it uses de via82cxxx_audio driver.
Can anyone help?

please post your lsmod and lspci output

OK:
lsmod:

Module Size Used by Not tainted
ppp_async 7520 1 (autoclean)
ppp_generic 15452 3 (autoclean) [ppp_async]
slhc 5040 1 (autoclean) [ppp_generic]
parport_pc 14724 0
parport 23264 0 [parport_pc]
uhci 24560 0 (unused)
usbcore 58144 1 [uhci]
via82cxxx_audio 18936 0
ac97_codec 9512 0 [via82cxxx_audio]
soundcore 3332 2 [via82cxxx_audio]
8139too 15272 0 (unused)
mii 2240 0 [8139too]
serial_cs 4656 0 (unused)
ds 6568 2 [serial_cs]
yenta_socket 9632 1
pcmcia_core 38112 0 [serial_cs ds yenta_socket]
ide-scsi 8048 0

lspci:
00:00.0 Host bridge: VIA Technologies, Inc. VT8363/8365 [KT133/KM133] (rev 80)
00:01.0 PCI bridge: VIA Technologies, Inc. VT8363/8365 [KT133/KM133 AGP]
00:07.0 ISA bridge: VIA Technologies, Inc. VT82C686 [Apollo Super South] (rev 42)
00:07.1 IDE interface: VIA Technologies, Inc. VT82C586/B/686A/B PIPC Bus Master IDE (rev 06)
00:07.2 USB Controller: VIA Technologies, Inc. USB (rev 1a)
00:07.4 Bridge: VIA Technologies, Inc. VT82C686 [Apollo Super ACPI] (rev 40)
00:07.5 Multimedia audio controller: VIA Technologies, Inc. VT82C686 AC97 Audio Controller (rev 50)
00:09.0 Communication controller: Conexant HSF 56k HSFi Modem (rev 01)
00:0a.0 CardBus bridge: Texas Instruments PCI1410 PC card Cardbus Controller (rev 01)
00:0b.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL-8139/8139C/8139C+ (rev 10)
01:00.0 VGA compatible controller: S3 Inc. VT8636A [ProSavage KN133] AGP4X VGA Controller (TwisterK) (rev 01)

It appears everything is working ok... Try logging in as root and see if you don't get sound that way. If you do then you just need to change permissions to 777(I think) for /dev/mixer. If not then keep asking.

Have you run a mixer program to check the volume settings? If not, it's also possible that your sound is turned down all the way or muted. This usually only happens with ALSA, but it is possible for it to happen with a kernel sound driver.

I have a compaq 715us laptop and I am pretty sure the same specs and mine is running fine, after I recompiled the kernel and selected via sound card.

If the sound card is not listed in lspci does that mean it's not supported and theres no chance of it working?

I use the same sound card
If /sbin/modprobe via82cxxx_audio worked from the CL, then try inserting into rc.modules should work too.

I have a different soundcard. A CS4232 on an old Toshiba Tecra 520CDT. I haven't had any luck getting the sound nor APM working. I was just wondering if the sound card must be listed in lspci for it to be supported.

Ok
I've follwed advice and recompiled my kernel with just sound card support and then installed the alsa driver, alsa lib and alsa utils as recomended. Still there's no sound on my laptop. I did /sbin/modprobe via82cxxx_audio and got the following answer:

/lib/modules/2.4.20/kernel/drivers/sound/via82cxxx_audio.o.gz: init_module: No such device
/lib/modules/2.4.20/kernel/drivers/sound/via82cxxx_audio.o.gz: Hint: insmod errors can be caused by incorrect module parameters, including invalid IO or IRQ parameters.
You may find more information in syslog or the output from dmesg
/lib/modules/2.4.20/kernel/drivers/sound/via82cxxx_audio.o.gz: insmod /lib/modules/2.4.20/kernel/drivers/sound/via82cxxx_audio.o.gz failed
/lib/modules/2.4.20/kernel/drivers/sound/via82cxxx_audio.o.gz: insmod via82cxxx_audio failed

Any help???

Compaqs dont come with audio cables. These are not required to play CDs in windows, but are required to play CDs in Linux. Unless you put them in afterwards...

PS This is a problem I have myself.

Problem Solved!!!
Ok, finally I solved it. I am now listening to some great U2 CD's.
Here's what I did, step by step:
1.- Install the Kernel Source in /usr/src/linux
Do this by: a)mount the CD-ROM No 2 and then from the command line go to "mnt/cdrom/slackware/k" there you'll find the source code. Run the shell program: "$sh -install-packages" you'll then install the package called kernel-source-2.4.20-noarch-5.tgz.
2.- Download and install the ALSA packages (alsa-driver, alsa-lib, alsa-utils) follow the instructions on their web page.
3.- Using KDE, go to the Control Center, go to System Administration and then to Linux Kernel. Here you'll be able to choose wich modules to compile in to the kernel. Go to sound. Select Sound Card Support, VIA 82C686 Audio Codec, VIA 82C686 MIDI and OSS sound modules, deselect everything else.
4.- Update you rc.modules file according to the ALSA instructions
5.- Create the .asoundrc file according to the ALSA instructions
6.- Logout from X, and from the command line compile as follows:
$make symlinks dep
$make clean
$make bzImage
$make
$make install
$make modules
$make modules install

7.- Say a prayer. Reboot with your new kernel, go back into X with "startx"
8.- Enjoy the sound.
9.- If still there's no sound, try installing aumix, and getting the volume up, 'cause it is muted by default, so you'll need a mixer program like aumix or Kmix.

Hope this is helpful