problem with sound.. cant load the device driver

[xanjien]

ive just reformatted my cousin's pc but it seems that there's no sound.. so i checked the sounds and audio device and ive found out that theres still no audio device. i was sure that ive installed all the device driver in the motherboard cd so ive checked the device manager. all necessary drivers seems installed but Realtek AC'97 Audio for VIA (R) Audio Controller has this yellow ! at the left part.. the status for this driver is: Windows cannot load the device driver for this hardware. The driver may be corrupted or missing. (Code 39) i already tried to uninstall and reinstall it and download the latest driver for Realtek AC'97 but the problem still exist.. what should i do?

this is the computer profile ive got from belarc:

Operating System System Model
Windows XP Professional Service Pack 2 (build 2600) ECS P4M800-M7 1.0
Enclosure Type: Desktop
Processor a Main Circuit Board b
2.67 gigahertz Intel Pentium 4
16 kilobyte primary memory cache
1024 kilobyte secondary memory cache Board: ECS P4M800-M7 1.0
Bus Clock: 133 megahertz
BIOS: American Megatrends Inc. 080012 09/13/2005
Drives Memory Modules c,d
41.10 Gigabytes Usable Hard Drive Capacity
24.25 Gigabytes Hard Drive Free Space

TSSTcorp CD-R/RW SH-R522C [CD-ROM drive]
3.5" format removeable media [Floppy drive]

Maxtor 6E040L0 [Hard drive] (41.11 GB) -- drive 0, s/n E169F48N, rev NAR61HA0, SMART Status: Healthy 224 Megabytes Installed Memory

Slot 'DIMM0' is Empty
Slot 'DIMM1' has 256 MB
Local Drive Volumes

c: (NTFS on drive 0) 23.07 GB 14.92 GB free
d: (NTFS on drive 0) 18.03 GB 9.33 GB free

Network Drives
None detected
Users (mouse over user name for details) Printers
local user accounts last logon
Michelle
6/28/2008 8:00:19 PM (admin)
local system accounts
Administrator
never (admin)
Guest
never
HelpAssistant
never
SUPPORT_388945a0 never

Marks a disabled account; Marks a locked account None detected


Controllers Display
Standard floppy disk controller
Primary IDE Channel [Controller]
Secondary IDE Channel [Controller]
VIA Bus Master IDE Controller VIA/S3G UniChrome Pro IGP [Display adapter]
Samsung S/T 77E/76E [Monitor] (15.7"vis, s/n HVAT206838, February 2002)

Bus Adapters Multimedia
VIA SATA RAID Controller
VIA Rev 5 or later USB Universal Host Controller (4x)
VIA USB Enhanced Host Controller Realtek AC'97 Audio for VIA (R) Audio Controller
Unimodem Half-Duplex Audio Device
Communications Other Devices
D-Link DFM-562IS HSFi PCI Modem

VIA Rhine II Fast Ethernet Adapter
primary Auto IP Address: 10.1.6.22 / 16
Gateway: 10.1.0.1
Dhcp Server: 10.1.0.1
Physical Address: 00:14:2A:7D:A6:B5

Networking Dns Servers: 58.71.1.37
58.71.2.7
A4 Tech USB PC Camera
Standard 101/102-Key or Microsoft Natural PS/2 Keyboard
Microsoft PS/2 Mouse
USB Root Hub (5x)