Ubuntu – Ubuntu 14.04 couldn’t detect nvidia graphic card (not even detect the model of card)

I am pretty new to Linux and I am working to install Cuda, which requires the Nvidia Graphic Card to work. My laptop is Lenovo Y50-70 with a GTX960M card. My system is Ubuntu 14.04.

This is the result I got from the system:

jinchao@jinchao-laptop:~$ sudo lshw -C display
[sudo] password for jinchao: 
  *-display               
       description: 3D controller
       product: NVIDIA Corporation
       vendor: NVIDIA Corporation
       physical id: 0
       bus info: pci@0000:01:00.0
       version: a2
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress bus_master cap_list rom
       configuration: driver=nvidia latency=0
       resources: irq:51 memory:d0000000-d0ffffff memory:a0000000-afffffff memory:b0000000-b1ffffff ioport:4000(size=128) memory:b2000000-b207ffff
  *-display
       description: VGA compatible controller
       product: 4th Gen Core Processor Integrated Graphics Controller
       vendor: Intel Corporation
       physical id: 2
       bus info: pci@0000:00:02.0
       version: 06
       width: 64 bits
       clock: 33MHz
       capabilities: msi pm vga_controller bus_master cap_list rom
       configuration: driver=i915 latency=0
       resources: irq:47 memory:d1000000-d13fffff memory:c0000000-cfffffff ioport:5000(size=64)

I have tried several solutions described in many posts, like:
Ubuntu and ASUS G750JM, GTX860M / Nvidia problems,
How do I get Ubuntu to recognize my nvidia graphics card?,
Why does Ubuntu 14.04 not recognize NVIDIA GeForce 310M hardware?,
and many else. Unfortunately none of them works for me. I even try to install ubuntu 15.04, but the same problem still exists.

It seems my problem is a little different from most the post. In most post, at least when they run sudo lshw -C display, the system can detect the correct model of the graphic card, while in my case, it only detects product: NVIDIA Corporation.

Can anyone help me? Really apreciated !