Gigabyte GA-P55A-UD4P ver. 1.0 Motherboard Sound Issue

I have a Gigabyte GA-P55A-UD4P ver. 1.0 motherboard and my problem is, whenever I play a video using my browser which is a Firefox, the sound randomly goes on and off.
And when it totally turns off, a reboot will fix the problem and then after a while, the same thing will happen. Is this an issue with my browser or with my motherboard itself?
Where can I find the drivers for my motherboard as I lost the disk that comes with it when I purchased it.
Thanks.
