Shame I was out and about shooting guns today otherwise I'd of popped by
As for the OBS bit, nvwgf2um.dll is related to nvidia drivers so my recommendations (technically a compilation of ideas ranging from the dev team to simple basics) are the following (and like regular tech support, I don't mean to make you feel stupid, I'm just running through the numbers):
1) Try running OBS as admin
2) Ensure Nvidia drivers are all up to date
3) If drivers are all up to date, reinstall
4) If problem persists, remove Shadowplay as the capture feature might be butting heads with OBS's capture
Related to OBS settings:
1) Use x264 for encoding
2) Make sure it's detecting and using the correct video adapter (which is to say your graphics card)
In regards to monitor capture:
1) Don't use monitor capture. Use "Window capture" and set the parameters to fit only where the game displays
2) Make sure your upload bitrate matches up with the quality you're trying to stream. Monitor captures tend to require a higher than normal bitrate for the same quality so you'll have to compensate. Easiest way to fix this is downscale your resolution with the "downscale resolution" option in the video settings tab.
3) Use CBR, not VBR
If you're curious as to the settings I use, let me know
