D700 mirror stuck up

hi

after i pressed shutter the mirror went up and never came down ... there is no error massage or anything ... the mirror works but it always starts from up then comes down and again goes up and stays .. from view finder the view is blocked because of that ... please help me ...

Maybe you are stuck in "LiveView" mode?
Did you try to remove battery and/or do a two buttons reset?

Let us know if you find the trouble.