I was advised to do an Archive & Install, without preserving info to see if it would fix a weird slowness issue.
I just did the Archive & Install, and when it restarted, it showed my name and photo, but it wouldn't accept my password. I can't login. All I can do is restart or shut down.
I rebooted from the install CD. Same thing.
I rebooted in safe mode. Same thing.
Are you using Filevault?
Are you using Firmware password protection in Mac OS X ...
It would block usage of all the startup keys, like C, N, T, D, CMD+s, CMD+Option+p+r, CMD +v, Option, and Shift, as well as booting from anything but the Hard Drive.
Retrieving data ...