Still can't install cuda correctly

I didn’t succeed to run any of the samples in cuda-9.
I tried different drivers of nvidia, different ubuntu kernel, different cuda version but non of these worked!

My setting is like so:

Ubuntu 16.04 LTS kernel 4.4.0

GeForce GTX 950M

nvidia-smi

Fri Feb 16 23:36:12 2018       
+-----------------------------------------------------------------------------+
| NVIDIA-SMI 384.111                Driver Version: 384.111                   |
|-------------------------------+----------------------+----------------------+
| GPU  Name        Persistence-M| Bus-Id        Disp.A | Volatile Uncorr. ECC |
| Fan  Temp  Perf  Pwr:Usage/Cap|         Memory-Usage | GPU-Util  Compute M. |
|===============================+======================+======================|
|   0  GeForce GTX 950M    Off  | 00000000:01:00.0 Off |                  N/A |
| N/A   40C    P0    N/A /  N/A |    177MiB /  4044MiB |      0%      Default |
+-------------------------------+----------------------+----------------------+
                                                                               
+-----------------------------------------------------------------------------+
| Processes:                                                       GPU Memory |
|  GPU       PID   Type   Process name                             Usage      |
|=============================================================================|
|    0      1231      G   /usr/lib/xorg/Xorg                           138MiB |
|    0      2069      G   compiz                                        35MiB |
|    0      2254      G   unity-control-center                           1MiB |
+-----------------------------------------------------------------------------+
cat /proc/driver/nvidia/version

NVRM version: NVIDIA UNIX x86_64 Kernel Module  384.111  Tue Dec 19 23:51:45 PST 2017
GCC version:  gcc version 5.4.1 20160904 (Ubuntu 5.4.1-2ubuntu1~16.04)

I tried for example:

/usr/local/cuda-9.1/samples/0_Simple/matrixMul$ ./matrixMul

And I get that error:

[Matrix Multiply Using CUDA] - Starting...
CUDA error at ../../common/inc/helper_cuda.h:1160 code=35(cudaErrorInsufficientDriver) "cudaGetDeviceCount(&device_count)"

What I’m doing wrong? Do you suggest anything to test?

CUDA 9.1 is not supported by 384.111

That is what that error message means.

Should I reinstall everything (cuda, driver) and test another driver or just the driver?

If you want to keep your 384.111 driver, you could install CUDA 9 instead of 9.1. CUDA 9 should be compatible with 384.111. Otherwise if you want to use CUDA 9.1, you will need to install a more recent driver.