Alienware 15 R3 Freezing

Hi,

I just got my brand new Alienware 15 r3
Nvidea 1070
i7
128SSD + 1TB
16GB RAM

I just bought it and was hoping for a very good gaming performance. But for some reason, I got problem even before I got any games. I'm using steam. But whenever I started downloading any games from steam, my mouse would freeze, the kind of freeze you got in a low fps game. Any idea why and how to fix it?

Thanks!