Ringtone Help!!!

[anyfingcool]

I have had my I900 since just before xmas, and love it, except 1 thing, for the second time now my ringtones have gone a bit weird, i can go to the settings to try and change it but once i have selected the tone i want when i go to exit ( tapping X or ok) nothing happens and i cant get rid of the ringtone select screen, it just resets its self to the orignal, its realy doing my head in now as i have to put up with what ever ringtone the phones wants to play lol, i had this prob once before and had to format the phone (advice from samsung ) any ideas would be hugely appreciated, as would really like to not have to reformat the phone again, it will take ages to get it back to how it is, is there a way of setting the ringtone from the registery?? so i dont have to use the stupid menu!!

Thanks in advance