In the past week, my first-gen iPhone seems to have decided that the time has come for me to move on to a new 3GS. First my Wi-Fi stopped working. Then I upgraded to 3.0. When I try to activate "Find my iPhone" it doesn't work (but maybe that's because I don't have a built-in GPS). But now, it seems not to ring when I'm called (yes, I checked to make sure my ringer is turned on).