I was attempting to do the "delete all settings and data from iPhone" from within the iPhone. After about half an hour or so, the bar hadn't moved at all, so I held the sleep and home buttons to do a hard reset. Now the iPhone will just load the Apple logo and then go black. The same thing happens when I plug it into my Mac. This is an iPhone 3G. Anybody have any advice? EDIT: Apparently holding down the home button while plugging into the Mac did the trick.