This question is an exact duplicate of:
From my previous question that people closed because they could not answer it:
I was trying to install openvpn from this tutorial and unlimited vpn from here. I had internet but, when I shutdown my computer and turn it back on, I cannot have Internet access even if I'm connecting to the wifi. It's not a hardware problem because when I try the live cd, I have internet access.
How to fix that?
Here is the solution.