When you download the game and delete monika first:

Sayori says for example: Who am i?, Then it closes by itself, Then when you try to open it again, It shows a END text and shows Sayori hanging on a rope.

When you see Just Monika, Then delete her file:

For example, Monika says "DID YOU DO THIS TO ME?" And she trys to bring herself back, but can't. And so she closes the file, and she restarts the game so shes not there, whenever you try to bring her back to the character files, and go to the file, click "New Game", a message will appear and say "Please stop playing with my heart, i dont want to come back."