No Sound on Windows 8 on Macbook Pro 13'' Late 2011

I'm using Macbook Pro 13'' Late 2011 and my CD ROM drive is broken so i installed Windows 8 using USB drive instead.

The bootable USB drive created by Boot Camp Assistant didn't work. When Boot Camp Assistant restart the machine, the machine did boot from the USB but then i got a black screen with the message that "No bootable medium found....". Note that this way worked on my friend's Macbook Pro 13'' 2012 model.

I then used Disk Utility application to create a Windows 8 bootable USB stick on my Macbook Air 11'' mid 2013. It worked on both my Macbook Air and Macbook Pro. I could setup Windows 8 successfully on both machines but sound problem still happened on Macbook Pro.

After that, I tried Driver Genius program to backup the working sound driver on Windows 8 from my Macbook Air and even from my friend's Macbook Pro then restored it on my Macbook Pro but still no luck.

Some people on the net said because I installed it using EFI and then the sound driver didn't load properly (only with my current model of Macbook Pro). Installing it using Legacy Boot Loader (Master Boot Record), the sound really worked. Here is how i did it http://vathanakmao-technotes.blogspot.com/2017/01/install-windows-7-on-macbook-pro-using.html