Can you choose to boot to primary or secondary and get to the login promt? If so, try clearing the passwords by pushing the clear button for 5 seconds. That will let you into the console without authenticating. Once in, you can use the "erase startup-config" command to reset to factory defaults.
But it kind of sounds like the software has gotten erased or corrupted, which won't happen during the normal factory reset that you tried. In that case, you can use xmodem from the boot menus to transfer a new software image to the switch and boot. It will take 20 or so minutes to transfer but it will work.