the changes from 16 to 23 or 24 are SO great that really none of the settings in your fedora 16 home folder will work in 23
I need to recover my root ID and password....
do to forum rules i can not go into too much detail
boot into "single user mode" and reset it
( unless you password protected the boot partition )
then use the install CD ( disk1 of 4) and boot into rescue mode and change it