This is my first post and first problem in Nokia N900. I switched off my N900 and switched it on again and It hung up with five dots after booting up. When I remove sim card and try to start with only battery and it works right. when I insert sim card and try to switch it on, only dots appear and shows some process running behind. I tried this things : * Deleted contacts from the sim card * Enabled R&D mode and switched on. same issue. booting up and dots. * Switched off mobile and taken out battery and connected with usb and then switched it on and inserted battery. * Removed battery and tried to switch on without battery to drain out any charge. * Tried sim card on other mobile and sim works right. * Inserted different sim card on N900 and switched it on. same problem. * Battery is almost fully charged (~80%) Mobile works ok without sim card. So I can say now my Nokia N900 is only computer and not computer - phone...!!! Has anyone experienced similar problem?