I have the same problem with no audio device. However, there is no sound icon in my device manager

dis you check if you have some problem with the Driver?
Check Device Manager in Control Panel

How do get into Windows Device Manager

How To Find And Open Device Manager In Windows 7


Also you can chek Audio status in Sound Devices an Adio i( look for "speaker" icon


Personalizing Your Work Environment in Microsoft Windows 7

How to Enable Audio Device in Windows 7

Open Device manager and right click on "Realtek HD Audio"
Select 'enable'
Right click on the speaker icon in the taskbar and select 'Playback devices' ensure that Realtek is checked as the default speaker device
Right click alongside the speaker icon and make sure they are not disabled
Use the 'Test' facility to check the audio
You may have to update the driver as well

click start control panel on the left select hardware and sound then select manage audio devices then recording you should see a microphone right click select enable windows 7
click start control panel hardware and sound manage audio devices playaback you should see your speakers right click select enable or you might have to configure them this option will be at the bottom of of the playback list windows7
click start control panel sounds and audio devices you can adjust the volume there also select speaker volume you can change your settings there you can also tick in the box place icon in taskbar for any further changes to your sound setting by right clicking on the speaker icon in the taskbar(bottom of screen)
hope this helps

Uninstall and reinstall the sound or audio driver.

1. Open device manager and expand the sound, video and game controller
1. For XP: Control panel (classic view)/Systems/Hardware/Device Manager/sound, video and game controller.
2. For Vista:Control panel (classic view)/Device Manager/sound, video and game controller.
2. For Win 7:Control panel (small icons)/Device Manage/sound, video and game controller.

2. Right click on the sound and game controller and uninstall the driver (usually the name of the driver is realtek high definition audio driver).
3. Restart the NB. The driver will automatically be reinstalled.
4. Test the sound.

check if your sound settings is not MUTE
check your audio device status in device manager

• look for my computer icon, right-click then PROPERTIES
• select HARDWARE > DEVICE MANAGER
• check if audio device has "?" or "!"
• click refresh button or update driver
  

Go to the following webpage: http://support.microsoft.com/gp/no_sound & run the automated troubleshooting service for sound by microsoft, there is a good chance of your issue getting resolved....

Please reinstall the Audio Driver. Uninstall the Audio Driver from the Device Manager window and then select Scan for hardware changes. The Audio Driver will be reinstalled. If you have downloaded the Updated Audio Driver, then you can directly reinstall it to resolve the issue.

1. Lets start with the obvious. Make sure the volume mixer control is not muted. This is usually a speaker icon at the bottom of the screen. If you do not see this then go to control panel, sounds and audio devices, and make sure nothing is muted.
2. check device manager. This can be done in Win XP by right clicking my computer, properties, hardware, then click device manager. Alternative way to enter device manager is by clicking start menu, control panel, system (performance and maintenance), hardware then device manager.

In the deice manager window see if any question marks or exclamation points are visible.

If so, see if it the mark is for an audio device.

If it is an audio device, uninstall the device.

Next, try to install the sound card driver again. If that fails, the enter the device manager and uninstall the sound card again, restart the PC, ignore the hardware manager, and try to install the sound card driver software again.

the yellow icon means that there is a problem with the device drivers for your audio. Find the manufacturer name, and model number for your audio device, delete the present audio drivers, the download fresh driver files from the manufacturer's website

Hi,

Check Control panel - >System -> Hardware ->Device manager ->sound video an game controllers.and make sure there is no exclamantion mark and also check other devices to see if you require any further audio drivers..
maybe youhave re-install your audio drivers
Cheers!!!