This evening I ran the software update on my Galaxy S3. (Sorry I don't know which version to). On the reboot the phone just hangs on the Samsung logo and won't go any further. I have tried a factory reset but the phone just hangs at the same point. This is the 2nd time this has happened to me. Last time I had to send it to the shop for repair and I was without the phone for several weeks. Why is this happening and is there any way I can fix it?