I know this is a stupid question, but since I'm preparing my device to android 4.3, so I think its still better to ask before doing anything. After performing a factory reset, will all the apps installed in my device be deleted? What about those stored in internal sd and external sd? Everything will be gone? Also is there any way to backup my calendar entry? I'm using 'cal', well sometimes S planner, and I stored all the calendar entry in my device, not syncing with my email account. Thank you so much!