If the appliance still works ok but you cannot see the lcd display screen because of the wwwwww's this will be down to a faulty screen.
Now the screens are part of the control board so if its faulty then it will need to be replaced.
But as to resetting it what you can try is pull the plug out from the socket and leave it a few hours if you have left it that long already, As this may allow the electronics to reset.
But if that doesn't work then it will proberly need to have the control unit replaced.
So yes this can be repaired by a service technician so you can either call Siemens out direct or a local service technician in your area will be able to repair it for you.