my iphone rings but the screen is totally black. i got a new iphone and want to back up, what do i do?

If you are not able to access the iPhone's screen, you will not be able to back it up. This is where previous backups would have come in handy. Of course, you can still contact Apple Support directly for assistance with this. To do so, simply select the "Get Support" link in the upper right-hand side of this forum's web page.