You need to make sure hello.d is in the current dirdir C:\D does hello.d show up?If not, then dmd can't find it and you have to tell it where it is or be in the right location.type dmd ThereIsNowFileHere12342123242231231412.d and you will get the same error message.
You have to be right. I removed the directory and started making de hello world file again and now it works.
Thank you to everyone? Alex