Windows 7 Audio problems on Virtual Box

This has solved Windows 7 VM audio problems and now Windows 7 audio is working fine on Virtual Box running on my Mac OS

clipped from forums.virtualbox.org Audio on Windows Vista x64/Windows 7 guests SOLVED: For error "No Audio Device Installed". After some time of searching the net, I was finally able to get sound working in my virtual Vista Ultimate x64 install. All that I had to do was install a driver for the VirtualBox virtual soundcard hardware. No reboot was necessary. 1. I went to http://www.realtek.com.tw 2. I clicked on "Downloads", then on "AC'97 Audio Codecs". On the downloads page I downloaded the file with the description "Vista/Win7 (32/64 bits) Driver only (ZIP file)". 3. Once downloaded, I extracted the files and pointed the Device Manager driver installer to the "6303_Vista_Win7_PG537\6303_Vista_PG537\Vista64" folder. It found the driver and proceeded with installation. Once it was done the Device Manager refreshed itself and showed the sound card as installed and working.