Pilote audio introuvable plus de son !

Bonjour,
Depuis ce matin, je n'ai plus de son et aucun de mes lecteurs ne fonctionnent. Apres m'être un peu renseigné, j'ai cru comprendre qu'il me manquait un pilote audio. Dans le panneau de config, j'ai un point d'exclamation près de 'contrôleur audio multimédia'. Ma config donne ça :

Version du plugin
3.0.4 build 0
Version de la base
7
Nom de la machine
acer-9deb84ebb9
Date de la détection
07/12/2008 17:51
Système d'exploitation
Windows XP Edition familliale (build 2600) Service Pack 3
Navigateur web par défaut: Mozilla Firefox
Client e-mail par défaut: Microsoft Office Outlook
Antivirus: avast! antivirus 4.8.1296 [VPS 081206-0] 4.8.1296
Carte mère
SMBios version 2.2
Acer FC51GM
Bios: Phoenix Technologies, LTD R02-A1 01/19/2006 taille: 512Kb
Processeur
AMD Sempron(tm) Processor 3200+ (1808Mhz) (L1: 128ko L2: 256ko )
Chipset
Northbridge: NVIDIA C51
Southbridge: NVIDIA nForce 410/430 (MCP51)
Mémoire
Barrette de 512 Mo
Barrette de 512 Mo
mémoire windows (cette valeur ne correspond pas exactement à la
mémoire totale physique): 958Mo
Carte Graphique
nVidia Corporation C51G [GeForce 6100] C51G [GeForce 6100] (256 Mo)
Lecteurs CD/DVD
HL-DT-STDVD-RW_GSA-H11N JH02 (DVD-R sequential recording Recorder)
Generic DVD-ROM 1.0 (DVD-ROM)
Disque dur
ST3160812AS (149.05Go)
Generic USB CF Reader USB Device
GENERIC USB DISK DEVICE USB Device (1.83Go)
Generic USB MS Reader USB Device
Generic USB SD Reader USB Device
Generic USB SM Reader USB Device
Cartes PCI/AGP
Stockage
nVidia Corporation:MCP51 IDE
nVidia Corporation:MCP51 Serial ATA Controller
nVidia Corporation:MCP51 Serial ATA Controller

Affichage
nVidia Corporation:C51G [GeForce 6100]: C51G [GeForce 6100]

Multimedia
nVidia Corporation:MCP51 AC97 Audio Controller

Mémoires
nVidia Corporation:C51 Host Bridge: C51 Host Bridge
nVidia Corporation:C51 Memory Controller 0: C51 Memory Controller 0
nVidia Corporation:C51 Memory Controller 1: C51 Memory Controller 1
nVidia Corporation:C51 Memory Controller 5: C51 Memory Controller 5
nVidia Corporation:C51 Memory Controller 4: C51 Memory Controller 4
nVidia Corporation:C51 Host Bridge: C51 Host Bridge
nVidia Corporation:C51 Memory Controller 3: C51 Memory Controller 3
nVidia Corporation:C51 Memory Controller 2: C51 Memory Controller 2
nVidia Corporation:MCP51 Host Bridge
nVidia Corporation:MCP51 Memory Controller 0

Ponts
nVidia Corporation:C51 PCI Express Bridge: C51 PCI Express Bridge
nVidia Corporation:C51 PCI Express Bridge: C51 PCI Express Bridge
nVidia Corporation:C51 PCI Express Bridge: C51 PCI Express Bridge
nVidia Corporation:MCP51 LPC Bridge
nVidia Corporation:MCP51 PCI Bridge: MCP51 PCI Bridge
nVidia Corporation:MCP51 Ethernet Controller
Advanced Micro Devices [AMD]:K8 [Athlon64/Opteron] HyperTransport Technology
Configuration: K8 [Athlon64/Opteron] HyperTransport Technology Configuration
Advanced Micro Devices [AMD]:K8 [Athlon64/Opteron] Address Map: K8
[Athlon64/Opteron] Address Map
Advanced Micro Devices [AMD]:K8 [Athlon64/Opteron] DRAM Controller: K8
[Athlon64/Opteron] DRAM Controller
Advanced Micro Devices [AMD]:K8 [Athlon64/Opteron] Miscellaneous Control: K8
[Athlon64/Opteron] Miscellaneous Control

Bus Series
nVidia Corporation:MCP51 SMBus
nVidia Corporation:MCP51 USB Controller
nVidia Corporation:MCP51 USB Controller
Texas Instruments:TSB43AB22/A IEEE-1394a-2000 Controller (PHY/Link)

Périphérique USB
Alcor Micro Corp. 8-in-1 Media Card Reader (USB Reader)
Actions Semiconductor Co., Ltd D-Wave 2GB MP4 Player / AK1025 MP3/MP4 Player
(USB MASS STORAGE CLASS )
Chic Technology Corp. Browser Mouse (Wireless Mouse)
Clavier
Clavier standard 101/102 touches ou clavier Microsoft Natural Keyboard PS/2
Souris
Souris HID
Ecran(s)
LG L1900J(Analog)(LG Electronics Inc. (GoldStar Technology, Inc.) )


Merci d'avance pour votre aide !
cdlmt