Serial Nero 3.1.0.25 I've Tried So Many Times To Install Nero 8 From Free Download Sites. I Need A Serial # To Install On My PC?

I've tried so many times to install Nero 8 from free download sites. I need a serial # to install on my PC? - serial nero 3.1.0.25

I tried several times to point to Nero after unloading from different locations to install the fact that there is always free to download. But after trying to install, always requires a serial number. Can someone help me ... I really hope is lost.