Monitor wont turn off in Windows 10

Taskmgr or services.msc and start killing off random processes till you find it (maybe not too random, no sense in crashing your comp)?
Have you tried completely removing all traces of display drivers using DDU and reinstalling the latest drivers for your card from scratch?

Something to consider when the updater under Windows 10 keeps insisting on updating drivers and doing such a bad job at it.
And found it. I did actually have a program monitoring a directory that I completely forgot about. Now to see if I can get that changed to not keep my screen on. Thanks all!