To "finish" all nights and unlock nights 6 and 7, follow the steps indicated below.

Access the Start menu
Type in: %appdata%
Proceed to MMFApplications
Find the file titled "fn4" (without the quotes)
Open it with Notepad
Copy and paste the following within it: night=5 beatgame=1 beat6=1 test=1 beat5=1 beat7=1 beat8=1 scene=5