Problem with Voluson 730 Expert Touchscreen

I have a problem with a voluson 730 expert. The system boots correctly, but the touchscreen don't work, everything else works fine including both displays, the only problem is that touchscreen doesn't work. It doesn't show any error or something. I checked connections and all seems fine, voltages fine, neither physical damage on any board. If I disconnect the touscreen it doen't show error and stays the same, if i disconnect the whole keyboard the system shows an error and doens't start up. I thought that could be a software problem and tried to reload the software, but the manual is really useless for this purpose. Does anyone know how to solve this??? Does anyone know how can I reload the software using the restore partition??