Audio driver doesn't work at startup.

Hello,

I recently installed an audio driver, realtek high definition audio driver R2.01, for my netbook to update the driver but whenever I restart the computer, you hear no sound, it cuts off. I've installed it several times, it works perfectly well when I choose the option at the end of installation to restart at a later time, but whenever my computer goes off and on again, it doesn't work, needing reinstalling, please help.

Thanks.