DE2-70 Board Problem

Hi

I use Quartus 8.0 and Nios 8.0.I'm programming DE2-70 board.

when I configured Assignments->Device->Device and pin options->unused pins->As output driving ground,De2-70 board was programming but Nios hello_world example didn't work.

when I configured Assignments->Device->Device and pin options->unused pins->As input tri-stated and send the .sof file with Programmer, all leds except power led and 7-segment displays on DE2-70 board went out the light and didn't work any Nios C code.

What could be the reason of this problem ?