When i connect my mobile to computer via USB cable, i can transmit only images. When i changes it to file sharing the mobile gets disconnected. What should I do?
You could back everything up (see Backing up an Android Device) and flashing the firmware again. Since we don't know what kind of phone it is, we can't tell you how. Please join the Android Central community so you can tell us the make and model of the phone here in this conversation, and we can help you further.