I have a gigabyte motherboard EP45-UD3P revision 1.6. My OS is Windows 8.1, Logitech PC speakers, and I use iogear 2-port DVI KVM Switch (GCS932UB). I'm having problems ( no sound) from the realtek on sound system. I now want to install a Sound Blaster card and I need to know how to disable the onboard sound to do this. Any ideas/suggestions will be greatly appreciated. thanks in advance.