Hermanguy wrote: the Terminal window
I think it might be helpful to give us a better understanding on where you were just before the "terminal window". If that's a "tty" (you'll know because it's all you can see) then you don't have X running, which is why fluxbox is unable to find a screen.
Put another way, you need whatever display manager it is that fluxbox uses (gdm I guess?) to be running; it should present you with a graphical login. Is this not the case? If it isn't, it should be. In that case, we need to debug why it's not starting. The content of your /var/log/Xorg.0.log -- particularly (EE) messages -- will be useful in tracking that down.