Originally Posted by SirFluff
As I clearly said, I cannot turn it off or on, nothing I do, what ever combination of buttons I would do wouldn't change that.
If the device is completely frozen, you won't notice the screen change when you power it off. Nevertheless, the fully-charge-then-power-off procedure is what you need to do before attempting a factory reset.
None of what you described doing in your original post was the factory reset procedure, which is why davidfor offered you the correct procedure sequence.
If that doesn't work, I suggest telephoning Kobo Support.