Since you have a "U" CPU I assume you're on a laptop? Which means the standard setting is usually that it'll use the integrated (Intel) graphics, instead of the GPU.
First: Be sure to check for new drivers, for NVIDIA: --> https://www.nvidia.com/Download/index.aspx
Then do this:
1. Right Click on Desktop
2. Select nVidia Control Panel
3. In left panel select "Manage 3D Settings"
4. In right panel select Global Tab
5. Under "Preferred Graphics Processor" select "Auto-Select" and hit APPLY button
