I installed Virtualbox on Windows 10 machine and then installed ubuntu 14.04. But I have a problem with the internet access that I can't connect the ethernet network, while I still normally able to connect in my windows machine. And one thing that I want to ask is in my Network setting, the option Enable Network Adapter is disabled, I can not choose it, does anyone have an idea?
It's disabled because you accessing the settings of your VM while guest OS is running. You should shut it down first, and then try to use NAT instead of Bridged mode.
I had deleted the guest account on my instance and INSERTED my MAC address from hardware into Ubuntu network settings. I used Bridged adapter and PCNET fast III. (Virtual box on MAC)
This is my first answer so go easy on me!
I think you need to check the option that says “Cable connected.”