Help needed

Hey guys, Im just after some help as Ive tried everything i can think of to resolve this issue myself.

Basically I just built a computer for my parents installed the OS everything works fine, except i have no sound output from the motherboard. Ive checked the BIOS for any settings that may need tweaking to make it work, nothing out of place there. So i went to the place i bought all the parts from and asked them about any problems, they mentioned something about there being an issue with some new HD graphics cards and that they can sometimes re-route the sound output to a port on the GFX card as opposed to letting it go through the motherboard.

So they gave me some simple to follow instructions to resolve the problem taken from the manufacturers own website. Tried these instructions out, only to find that some of the things i should be looking for arent there. Microsoft UAA is missing. When i try to open up Volume control panel from the entertainment menu in start menu, it puts up a message saying "No active mixer devices available" and then says it is going to close the program. Ive tried to download and install Microsoft UAA from the internet to no avail, it still does not appear in the device manager. Im really stuck for options atm so any help would be greatly appreciated.

Here are some specs for you to go off:

Mobo: Gigabyte GA-P35_SG3
GFX: EVGA GeForce 8500 GT

Thanks in advance and i look forward to replies from anyone who can help me with this. Eddie

Visit the Realtek web site and download the driver that matches your system
http://www.realtek.com.tw/download [...] wnTypeID=3

Ive been to this site and tried downloading and installing drivers for my system already, i still cannot get sound from my computer