No Audio Device ??

hey guys.just recently installed Windows Xp Pro on my computer. There was no sound at all even when playing songs. So I went to my Motherboard website and downloaded everything that I needed. The sound drivers where RealTek AC97. I can play songs and movies with sound now. No problem. But Windows doesnt play any sounds. Like logging on or logging off, emptying recycle bin, someone signing into msn messenger etc. When I go to control panel and sound and audio devices properties it says No Audio Device. When I go to the sounds tab n try to play a windows sound is says 'Windows cannot play the sound %SystemRoot%\media\Windows XP Critical Stop.wav. Your sound card may be in use.' Also I when I play something on a website there is no sound at all. Like videos or watever. this is really annoying.
I have a packard bell I-xtreme. Pretty old like. ( 4 years old maybe). here r sum of the info about it:

Motherboard Properties
Motherboard ID 06/26/2003-KM400-8235-6A6LYM4BC-00
Motherboard Name MSI MS-6786

Front Side Bus Properties
Bus Type DEC Alpha EV6
Bus Width 64-bit
Real Clock 167 MHz (DDR)
Effective Clock 333 MHz
Bandwidth 2666 MB/s

Memory Bus Properties
Bus Type DDR SDRAM
Bus Width 64-bit
Real Clock 167 MHz (DDR)
Effective Clock 333 MHz
Bandwidth 2666 MB/s

Chipset Bus Properties
Bus Type VIA V-Link
Bus Width 8-bit
Real Clock 67 MHz (ODR)
Effective Clock 533 MHz
Bandwidth 533 MB/s

Motherboard Physical Info
CPU Sockets/Slots 1
Expansion Slots 3 PCI, 1 AGP, 1 CNR
RAM Slots 2 DIMM
Integrated Devices Audio, Video, LAN
Form Factor Micro ATX
Motherboard Chipset KM400

Motherboard Manufacturer
Company Name Micro-Star International
Product Information (URL address blocked: See forum rules)
BIOS Download (URL address blocked: See forum rules)

1)Right click on 'My Compuer' and select 'Properties'.
2)Click on the 'Hardware' tab.
3)Click 'Device Manager'.
4)Expand 'Sound, Video and Game Controllers'.

Any yellow question marks?

Nope, no yellow marks at all. Everything seems to be working ok. Weird the way I can play songs and movies but windows doesnt play anything. I hope someone can help. its Confusing. lol

1) Go into 'Control Panel'
2) Switch to "Classic View" in the upperleft if not in Classic View.
3) Double click Sounds and Audio Devices
4) Click "Sounds" tab
5) Under "Sound Scheme" in the first box, select "Windows Default"
6) Just below that you can assign sounds to various events. Find the "Start Windows" choice. Left click on it once (it should now be highlighted)
7) From the 'Sounds" drop-down menu select "Windows XP Startup" option if not selected.
8) Do the same thing to other "Events" such as "Exit Windows" etc...

ALSO...
Make sure The Realtek AC97 Audio device is set as the default under the "Audio" tab and "Voice" tab. Under the "Volume" tab, make sure "Mute" is not checked under device volume. Double check your speaker settings under this tab as well.

reboot...

PWD, u r the man. It worked. where u said..

Make sure The Realtek AC97 Audio device is set as the default under the "Audio" tab and "Voice" tab. Under the "Volume" tab, make sure "Mute" is not checked under device volume. Double check your speaker settings under this tab as well.

Realtek AC97 wasnt set as default. Thanks very much mate.