I want to build an application that checks every second for certain windows and then react according to that.

My Goal:
I'm building the application for a pc in a Students Home with about 10 users. To create 10 different user accounts for windows will be annoying and crowded, because new people come in every year(or couple of months) and then old accounts have to be deleted and new ones created.

I want to build an application that accepts folderPaths or window names.

Lets say user1 creates a folder with the name "Susan" that she wants to protect (her personal files/picture/work will be stored there. She opens the application, selects the folder. The application saves the folder path and her password that she enters.

If the application detects that a user is trying to open/move/delete/copy/whatever that folder, the app must pop up a password box. Correct password gives her the freedom she wants, wrong password just ignores the open/move/delete/copy/whatever command.

Is it possible to do this?