https://medium.com/@medasuryatej/install-tensorflow-gpu-2-0-f4e215438199
I have encountered this problem before. When you use CUDA 8.0,the file cupti64_80.dll lies in C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v8.0\extras\CUPTI\libx64. I just fixed the problem by copying the dll into C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v8.0\bin, and the file cupti.lib in the same location into C:\Program Files\NVIDIA GPU Computing Toolkit\CUDA\v8.0\lib\x64.
On Nvidia Control Panel, there is a Developer-Manage GPU Performance Counters section. Default toggle is to limit access to GPU preformance counters to admin users only. But you must select 'Allow acces to the GPU prformance counters to all users'. Once toggled, access permissions to the cupti dll are resolved.