masoudalee,

Thank you for using the Dell Community Forum.

You will need to go into the controls and make adjustments in the projector mode.

Projector Mode – Select how the image appears:

Front Projection – Desktop (default)
Front Projection – Ceiling Mount – The projector turns the image upside down for ceiling-mounted projection.
Rear Projection – Desktop – The projector reverses the image so that you can project from behind a translucent screen.
Rear Projection – Ceiling Mount – The projector reverses and turns the image upside down. You can project from behind a translucent screen with a ceiling-mounted projection