Dell monitor U2713H error: settings can't be saved

We just bought a monitor U2713H direct from Dell.

When we click on Factory Reset, the monitor doesn’t go back to Factory default setting.

-In particular, Contrast/Brightness: 0.
In terms of Color Setting, Input color Format: None.
Preset Modes: Movie

-Then we click on Reset Color Settings, Input Color Format: RGB, Preset Modes: Standard.

-When click on Factory Reset again, Contrast/Brightness and Color Setting come back to the same condition as above (Contrast/Brightness are 0, Input color Format: None.
Preset Modes: Movie).

-After we try to set up Contrast/Brightness to 50/50, we shut down desktop or turn off the power button on the monitor. Then we turn on computer or turn on power button on the monitor, Contrast/Brightness are 0, Input Color Format: None, Preset Modes: Movie.

-In summary, all menu settings can’t be saved by the monitor and Factory Reset doesn’t work.

Any idea would be highly appreciated. Thank you a lot in advance