Stuck in authenticating

My client is stuck in authenticating and won't progress into the game client. I recently bought a alienware m17 r5 and the client works fine on my desktop, the problem seems to be only on the laptop.

I tried turning off firewall and do some port forwarding (not that I have any networking expertise) and I tried the hextech repair tool and it still didn't work.

Is there something else I can do? Please help.

Thank you.