Deleted OS of my Nspire CAS, can't send a new one

I deleted the OS of my TI-Nspire CAS Touchpad via the maintenance menu, but now I can't send a new one to it.
I was actually trying to get nLaunch on it, but that didn't send just nothing happens on the calc.
It is completely stuck at the "Operating System ot found. Install OS now." screen.
Even when I try to send a normal OS to it, nothing happens on the calc, however for both an error shows on the PC.
But it is not really useful:
I thought that maybe it would help to delete everything, so I did go to the maintenance menu and pressed 4.
But then I also couldn't send files anymore to the calculator, which I was able to do before...
Does anyone know what I have to do to get my nspire working again?
I was actually trying to get nLaunch on it, but that didn't send just nothing happens on the calc.
It is completely stuck at the "Operating System ot found. Install OS now." screen.
Even when I try to send a normal OS to it, nothing happens on the calc, however for both an error shows on the PC.
But it is not really useful:
Msg: hand-held returned an error (not caught).
Cause: hand-held returned an uncaught error. Please report log
I thought that maybe it would help to delete everything, so I did go to the maintenance menu and pressed 4.
But then I also couldn't send files anymore to the calculator, which I was able to do before...
Does anyone know what I have to do to get my nspire working again?