Cuda 8 at MSI GT70 Error

I need your help…
I install CUDA 8 at MSI GT70 laptop (GTX 770M).
Now I have error “Nvidia device is not removable” at the function “GetDeviceCount” and laptop freezes.
I tried to install several versions of drivers - does not help.
CUDA 6.5 work normally.
Can somebody help me?