I had several issues with that in the past, too. Usually, the culprit was the graphics card driver / the graphic card not supporting certain versions of CUDA. I recommend uninstalling the version you have installed right now and to install the CUDA 8 version and check if this works. If it does work with CUDA 8.0-PyTorch, you would know that it’s the graphics card (driver), and otherwise, it would need further exploration. Let me know what you find.
Btw. the best (or quickest) way to check CUDA availability is by
import torch
print(torch.cuda.is_available())