I would use a user account called Administrator, without password. Make this user, and only this one, auto-start a program to do all those things you want it to

I would use a user account called Administrator, without password. Make this user, and only this one, auto-start a program to do all those things you want it to. It's better than a .txt because it's easier to hide (you don't have to actually hide it this way) and the person that stole your notebook is more willing to wait a little for the default programs to load than when opening a file, especially a txt one. When he/she thinks it logged in successfully, the portrait of the thief is already in your inbox and your sensitive files encrypted/deleted.