How do i uninstall Realtek high definition audio

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After that you will need to disable it in the bios or when windows boots up it will auto-install the realtek again.
However you can run more than one sound card in windows, just make the new one the default card, you can still use the old one for headset use for something like voice chat.

Or you could just disable it from within the device manager in control panel and that should solve it too.

disable it in the BIOS. You can also try opening control panel/sound.... and chose your device in the drop down boxes.