Okay,I'll suggest something which usually works for me.
Go to Device Manager,select Sound,video and game controllers(most probably that's the name).You'll see a list,and from that,select the properties of your audio device (Like Realtek or VIA Audio etc) .From the next window that appears,select Driver Tab.Then click Update driver.Click on 'Browse my computers for driver software' option.Select the location of the installer of your driver software(Audio).Make sure you select the proper folder or it'll say,best driver already installed.So for example,I select the location of my driver as follows:
(Note that I selected the correct folder and the subfolder instead of selecting just the main folder and ticking include subfolders option)
And select the option 'Include subfolders'.Then click Next.It'll search for the driver,and once found,it will Install the driver automatically.
It should work.If it doesn't please post the error message.Also,make sure you install the proper driver according to your OS-X86 or X64.