Why won't my F80 Nikon turn on?

Its a film camera, its in great condition, and i know it works fine, i've used it before and the pictures develope just fine. I inserted Enercell lithium bateries that worked for a bit but after a short while the screen is completely blank and the camera dosnt turn on. It happened with the old batteries as well. But i turned the camera off and everything. Can someone please help me?

I think the F80 is the N80 in the States

Here is a link to the user manual

http://www.butkus.org/chinon/nikon/nikon_n80/nikon_n80.htm

The fact you can't see through the view finder tells me that the mirror is locked up or your shutter speed is so slow that the viewfinder is blank while the long exposure is in progress.