So I stupidly bought an iphone 3G from someone off of Craigslist when it wasn't charged, and when I got home I found it had a password. I tried calling the guy who sold it to me, but no answer. I'm trying to perform a "hard reset" to clear the data and the password so I can use the thing, but for some reason I can't even turn the phone off all the way, only put it into sleep mode. No matter how long I hold the home/ sleep buttons together the screen will only go blank and the apple logo won't appear. I held the buttons for 3 entire minutes solid and got nothing. As soon as I let go after the screen goes blank, the password screen just pops back up again showing it never powered off all the way. I've already had this thing for a couple weeks and I can tell that guy is not going to return my calls or give me my money back. Won't someone please help me clear this password and reset it to factory settings?