As per the previous post I have a similar problem with an SX1 buzzing and halting at startup. It has a new battery, a working Cingular SIM but still get the buzz/halt behavior at startup. Normal startup sequence, PIN validated OK, startup screen shown and then it buzzes and shuts down. I have used the *+#+On Button sequence at startup but startup just continues as per before and the problem still remains. Any thoughts pls on how to resolve this ?