néophyte mais passionné, j’avoue mon désarroi.
J’ai consulté des POST tels que:
http://forum.debian-fr.org/viewtopic.php?f=3&t=2962&hilit=ALSA+snddevices
ou
http://forum.debian-fr.org/viewtopic.php?f=8&t=8624
Après manipulation, il est arrivé que cela fonctionne, et puis au démarrage suivant, plus rien et la manip faite précedemment était pour le coup sans effet.
distribution :
Debian
noyau employé:
Linux debian 2.6.18-5-k7 #1 SMP Wed Oct 3 00:47:27 UTC 2007 i686 GNU/Linux
renseignements sur votre matériel : 
$ lspci
00:00.0 Memory controller: nVidia Corporation CK804 Memory Controller (rev a3)
00:01.0 ISA bridge: nVidia Corporation CK804 ISA Bridge (rev f3)
00:01.1 SMBus: nVidia Corporation CK804 SMBus (rev a2)
00:02.0 USB Controller: nVidia Corporation CK804 USB Controller (rev a2)
00:02.1 USB Controller: nVidia Corporation CK804 USB Controller (rev a3)
00:04.0 Multimedia audio controller: nVidia Corporation CK804 AC’97 Audio Contro ller (rev a2)
00:06.0 IDE interface: nVidia Corporation CK804 IDE (rev f2)
00:07.0 IDE interface: nVidia Corporation CK804 Serial ATA Controller (rev f3)
00:08.0 IDE interface: nVidia Corporation CK804 Serial ATA Controller (rev f3)
00:09.0 PCI bridge: nVidia Corporation CK804 PCI Bridge (rev f2)
00:0a.0 Bridge: nVidia Corporation CK804 Ethernet Controller (rev f3)
00:0b.0 PCI bridge: nVidia Corporation CK804 PCIE Bridge (rev f3)
00:0c.0 PCI bridge: nVidia Corporation CK804 PCIE Bridge (rev f3)
00:0d.0 PCI bridge: nVidia Corporation CK804 PCIE Bridge (rev f3)
00:0e.0 PCI bridge: nVidia Corporation CK804 PCIE Bridge (rev a3)
00:18.0 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] HyperTra nsport Technology Configuration
00:18.1 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Address Map
00:18.2 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] DRAM Con troller
00:18.3 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Miscella neous Control
01:06.0 Multimedia controller: Pinnacle Systems Inc. AV/DV Studio Capture Card
01:06.1 FireWire (IEEE 1394): Pinnacle Systems Inc. Unknown device 0015
01:07.0 Multimedia video controller: Conexant CX23880/1/2/3 PCI Video and Audio Decoder (rev 05)
01:07.1 Multimedia controller: Conexant CX23880/1/2/3 PCI Video and Audio Decode r [Audio Port] (rev 05)
01:07.2 Multimedia controller: Conexant CX23880/1/2/3 PCI Video and Audio Decode r [MPEG Port] (rev 05)
05:00.0 VGA compatible controller: nVidia Corporation NV44 [GeForce 6200 TurboCa che™] (rev a1)