I purchased my new Nokia 920 on Friday November 9, 2012. On Wednesday Nov 21st, my phone is locked up and I cannot use it. All that appears on the screen is the “Nokia” logo. I rechecked my charger cord, and tried different cables and outlets.
On my Samsung Galaxy II tablet, I had encountered a similar issue, and discovered that I needed to hold the power button in for 13-15 seconds. So, I tried that with my Nokia phone. But holding it in for more than 30 seconds did not fix the issue.
So off I went to the AT&T store where I purchased the phone. The sales rep was surprisingly quick with the solution, which worked. He held in both the Volume key (5) and the Power/Lock key (6) simultaneously, for a full minute. This does a soft reset of the phone.