Hey,
 
	I've just found a solution for this problem:
 
	Edit perefences of all selected files on the window below:
 
	 
	Select checkbox Run as administrator (I have polish version of windows, sorry) and click Apply
 
	Then click Change DPI setings below and set like this:
 
	 
	Then ok and apply changes.
 
	Now you can run MentalOmegaClient.exe, go to the options and set like below:
 
	 
	...and now works with any res you want, windowed or fullscreen on Windows 10.
 
	I hope it'll help some of you.
 
	cheers