I just followed the instructions to install the Verizon Software Upgrade Assistant from my S4, but have run into one small problem: the program is on my PC, but it won't detect my phone. I keep seeing the message "Connect your phone/tablet to the PC upgrade your device. If your device is already connected, disconnect your device and connect it again." But when I disconnect and reconnect the phone, nothing happens. I have transferred a lot of data between my phone and computer before, so the computer itself obviously recognizes the device. Is it possible that I disabled an app on the phone that needs to run for this to work? Any thoughts would be appreciated, as I'm at my wit's end.