D:\Distrib\Siacoin\sia-gpu-miner-win64>sia_gpu-miner
failed to get Device IDs: -1
I also can't run it on Windows 10 x64 Insider Preview. "MSVCR120.dll is missing". I have installed Visual C++, MSVCR120.dll is present in system32. When I put it directly to miner's folder it closes with error 0xc000007b.
With the newly provided GPU miner link this is the exact issue I have also now. Windows 8 with Visual C++ installed.
Seems to me like you might now have a gpu, either that or your gpu does not support OpenCL.
I have AMD Radeon 7970, I believe it's capable of that.