How can I use AirDroid to back up my Samsung Galaxy IIS (Epic) smartphone? Since I've had the phone (1-1.5 months), the Android OS has been upgraded once, and I keep getting a message urging me to upgrade again. However, the first time I upgraded, I lost virtually all of my personal files and, as I recall, even one or two apps that I had downloaded. The "upgrade" also prevented me from using the USB cable to transfer files between my phone and my PC. So I need another way to back things up before I install the next upgrade. I was hoping I could do that with AirDroid, but I'm not sure how to do it. Please help.