I've installed Knoppix 3.9 on an Acer TravelMate 2451WLCi and I can't get the sound working.

Hardware:
Intel® Celeron® M processor 410
Mobile Intel® 940GML Express chipset
ATI Mobility Xpress 200M

I tried alsaconf and got:
No supported PnP or PCI card found

sndconfig:
You don't seem to be running a kernel with modular sound enabled. (soundcore.o was not found in the module search path)

lsmod:
Module Size Used by
ub 18332 2
lp 13448 0
snd 46308 0
soundcore 11104 1 snd
agpgart 30512 0
autofs4 18820 1
af_packet 20104 0
ath_pci 53024 0
ath_rate_onoe 10632 1 ath_pci
wlan 102876 2 ath_pci,ath_rate_onoe
ath_hal 150480 1 ath_pci
8139too 25600 0
mii 7808 1 8139too
parport_pc 38596 0
parport 33480 2 lp,parport_pc
8250 41692 0
serial_core 21120 1 8250
unionfs 109944 0
sbp2 24456 0
usb_storage 63296 0
ehci_hcd 31752 0
ohci1394 33028 0
ieee1394 300600 2 sbp2,ohci1394
usbhid 42176 0
ohci_hcd 21896 0
uhci_hcd 31376 0
usbcore 101496 7 ub,usb_storage,ehci_hcd,usbhid,ohci_hcd,uhci_hcd
pcmcia 21776 2
yenta_socket 21896 1
rsrc_nonstatic 12160 1 yenta_socket
pcmcia_core 42272 3 pcmcia,yenta_socket,rsrc_nonstatic
video 18308 0
thermal 14984 0
processor 24552 1 thermal
fan 7300 0
container 7296 0
button 7168 0
battery 12420 0
ac 7556 0
rtc 13772 0
ext3 124552 0
jbd 65060 1 ext3
reiserfs 232304 1

lspci:
0000:00:00.0 Host bridge: ATI Technologies Inc: Unknown device 5a31 (rev 01)
0000:00:01.0 PCI bridge: ATI Technologies Inc: Unknown device 5a3f
0000:00:13.0 USB Controller: ATI Technologies Inc: Unknown device 4374 (rev 80)
0000:00:13.1 USB Controller: ATI Technologies Inc: Unknown device 4375 (rev 80)
0000:00:13.2 USB Controller: ATI Technologies Inc: Unknown device 4373 (rev 80)
0000:00:14.0 SMBus: ATI Technologies Inc: Unknown device 4372 (rev 83)
0000:00:14.1 IDE interface: ATI Technologies Inc: Unknown device 4376 (rev 80)
0000:00:14.2 0403: ATI Technologies Inc: Unknown device 437b (rev 01)
0000:00:14.3 ISA bridge: ATI Technologies Inc: Unknown device 4377 (rev 80)
0000:00:14.4 PCI bridge: ATI Technologies Inc: Unknown device 4371 (rev 80)
0000:01:05.0 VGA compatible controller: ATI Technologies Inc: Unknown device 5a62
0000:09:02.0 Ethernet controller: Atheros Communications, Inc.: Unknown device 001a (rev 01)
0000:09:04.0 CardBus bridge: ENE Technology Inc CB1410 Cardbus Controller (rev 01)
0000:09:06.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL-8139/8139C/8139C+ (rev 10)

Does anyone have any suggestions? I've searced the forums but couldn't come up with anything.

I followed the troubleshooting steps at alsa.opensrc.org. (I can't post the link since I've just been lurking the forums for a while) I got to step 4 where it checks to make sure your soundcard drivers are active. The lspci | grep audio turns up with nothing for me so I don't know which driver to use. I tried running modprobe snd-intel8x0 and snd-intel8x0m with no results.

I would recomend little bit more recent version of Knoppix (or maybe other distro) to see if it will recognize your card.
ASAIK cards used by Acer are very well handled by recent kernels.

Run Knoppix 5 or other live distro with >= 2.6.16 and check if ypu still have problems.

I attempted to download a more recent version of Knoppix, but I am unable due to network restrictions here. Do I need to update my kernel to recognize this sound card or can I download just a driver from somewhere?

You can always grab new alsa modules source and compile them.