|it started to install the ac'97 sound driver automatically with the found new hardware wizard|
You should install your driver by executing the .exe file downloaded from the Internet. (no unzipping whatsoever).
Again, make sure all sound drivers are uninstalled prior to installing the new driver.
If you try to download it (and dont worry it wont actually download because there is a major problem)
As far as I know the Realtek website works properly, if that is what you are pointing at.
So, make sure the driver is uninstalled and delete all driver files you downloaded so far. Then go here and download & execute the downloaded file and install the driver.
Hopefully this will be the last file you`ll have to download.
Google is your friend
Have a GREAT day!