Using dual monitors but I had to keep adusting the brightness and contrast on monitor 2 (a Samsung 23333.)
I found that it kept defaulting back to "Other applications control colour settings" rather than "Use Nvidea settings."
Try this to start with as a diagnostic:
1 Right click on the Desktop and open the NVIDEA control Panel. Look at "Choose how colour is set". It will probably be on "Other applications control colour settings " if you installed monitor software.
2. Type Colour Management to go into Windows Colour Management. Ensure under Devices that no Profile is loaded as this will over ride the Nvidea settings.
3. In the Advanced tab, in Windows Colour System Defaults, set the Device Profile set System default (sRGB IEC61966-2.1).
4. In the Devices tab, check [ ] Use my settings for this device, then click [ Add... ] and choose sRGB IEC61966-2.1. Set this as the default.
5. Try a reboot to make sure it retains the NVIDIA settings and not the "Other Applications Control Settings".
Mine now retains the setting on start up.