Samer,
Don't bother loading in the operating system if you have figured out why the sounds weren't changing. It sounds to me like the group thing was the reason. If you don't like that the styles don't change until the beginning of the next measure, remember that the Rolands, Korgs and Yamaha all have to do this and there is no way to change this on their boards where at least Ketron has given you an option.
Hang in there, it sounds like you are figuring a lot of stuff out as you go.
George Kaye
Kaye's Music Scene