http://www.d-a-l.com/hardware-scan.html
I have went their and mostly found nothing heres my comps information
OS Information:
Property Value
OS Name Microsoft Windows XP Home Edition|C:\WINDOWS|\Device\Harddisk0\Partition1
Service Pack 1.0
OS Manufacturer Microsoft Corporation
Windows Directory C:\WINDOWS


Processor:
Property Value
Current Clock Speed 1659
Description x86 Family 6 Model 8 Stepping 1
Manufacturer AuthenticAMD
Name AMD Athlon(tm) XP 2000+


Memory (RAM):
Property Value
Bank Label Bank0/1
Capacity 268435456

Total Memory Deteced in Hardware: ~256 MB
Memory Reported to Operating System: 223MB

Disk Drives:
Property Value
Description Disk drive
Manufacturer (Standard disk drives)
Model WDC WD400BB-75FJA1
Media Type Fixed hard disk media
Size 39999536640 (~37 GB)
Number of Partitions 1


Installed Printers:
Property Value

Motherboard:
Property Value
Manufacturer ASUSTek Computer INC.
Model
Name Base Board
Part Number
Product A7V400-MX
Version 1.03


BIOS:
Property Value
Manufacturer Phoenix Technologies, LTD
Name Phoenix - Award BIOS v6.00PG
Release Date 20041221******.******+***
Version KM400A - 42302e31


Monitor:
Property Value

Keyboard:
Property Value
Description Standard 101/102-Key or Microsoft Natural PS/2 Keyboard


Pointing Device:
Property Value
Manufacturer Microsoft
Name PS/2 Compatible Mouse


Sound Card:
Property Value

Video Card:
Property Value

DirectX Installation:
Property Value
Version 6.03.01.0146


Modem:
Property Value
Model Generic SoftK56
Name Generic SoftK56


Network Adapters:
Property Value
Description VIA Compatable Fast Ethernet Adapter - Packet Scheduler Miniport
Description RAS Async Adapter
Description Packet Scheduler Miniport
Description WAN Miniport (L2TP)
Description WAN Miniport (PPTP)
Description WAN Miniport (PPPOE)
Description Direct Parallel
Description WAN Miniport (IP)
Description Packet Scheduler Miniport

External Ports:
Property Value
External Reference Designator
External Reference Designator
External Reference Designator
External Reference Designator
External Reference Designator
External Reference Designator
External Reference Designator
External Reference Designator
External Reference Designator USB1
External Reference Designator USB2
External Reference Designator USB3
External Reference Designator USB4
External Reference Designator USB5
External Reference Designator USB6
External Reference Designator VIDEO
External Reference Designator Line In
External Reference Designator Line Out
External Reference Designator Mic In
External Reference Designator CD In
External Reference Designator Aux In
External Reference Designator Front Panel
External Reference Designator ETHERNET
External Reference Designator IE1394_1
External Reference Designator IE1394_2

Expansion Slots:
Property Value
Slot Designation PCI1
Slot Designation PCI2
Slot Designation PCI3
Slot Designation AGP
PLZ help ThanKS plus i need realtek Ac 97 too

did you install anything new before your sound went ?
have you tried reinstalling the drivers?

Welcome to D-A-L play gamer!

As brain_damage mentioned you should start from reinstalling the drivers!
Here is the link to your audio drivers: http://dlsvr03.asus.com/pub/ASUS/mis...0/WDM_3663.zip

Since your audio is an onboard device you should make sure that it is enabled in the BIOS. Refer to your manual to find out how to do that (manual: http://dlsvr03.asus.com/pub/ASUS/mb/..._a7v400-mx.pdf)

The other thing is that if you have the front audio and the back audio inputs on your computer tower then the back ones most likely won't work if the front is working and vice versa so make sure to check them all.

Make sure that no audio device is muted! In order to view your audio settings go to "START"->"Settings"->"Control Panel"->"Sounds and Audio Devices". On the window that will open click on the "Advanced..." button under "Device volume" settings. That will open the volume control panel of your audio devices. Make sure that the volume "zippers" are high enough and that nothing has the "mute" option checked!

Question:
- What exactly happened before the audio went def? (did it stop sudenly or maybe after the restart?)

Good luck!