Audio device not installed Win7x64

[MacNala]

I am a newcomer to Virtualbox so pardon any misunderstandings.
I have setup virtualbox in my Windows 7 64 bit Host machine and have installed a Windows 7 64 bit Guest successfully.
However the guest machine reports that 'No Audio Output Device is installed'.
I have gone to the settings and checked that the audio is enabled and the audio controller is ICH AC97 and the Host Audio Driver is Windows DirectSound.
Rebooted without success.
I have gone to the Device Manager in the guest and under other devices there is an entry 'Multimedia Audio Controller' but I am unable to determine the correct driver to choose and none is found using the update driver option.
The host reports for audio in the device manager a 'High Definition Audio Device'.
The driver details for which are
dmk.sys
HdAudio.sys
ksthunk.sys
portcls.sys
SysFxUi.dll
WMALFXFGFXDSP.dll
all from Microsoft.

How do I get sound to work in my guest Windows 7?

[Perryg]

This has been covered hundreds of times here.
You need to start the guest and go to realtek.com.
Download and install the drivers and reboot.
Then force Windows 7 to do an update.
Reboot again. (Hey it a Windows thing)

[MacNala]

Thanks for the reply. I had searched the forums for 'no audio output device installed' but the results were negative. I did find a lot of entries talking about no sound and the instructions to instal the drivers was noted. I apologise if I caused you any trouble in replying to what you might think of as the hundred and first time. I think you might agree that I did provide all the information and had searched for an answer.

[Sasquatch]

Searching for "Windows 7 audio" (you can add the 'driver' part too if you want) should have given you plenty of results.