su - Authentication failure - reinstall fedora ?

[KW]

On 08/30/2014 01:13 AM, Angelo Moreschini wrote:
> Hi, after that I installed fedora 20, I am not able to get the
> login as su. When I try to sign me as super user, I always get the
> answer "Authentication failure".
> 
> I don't think that I really type wrong the password that I set at 
> install time:/I typed it twice/. Rather I think that they are some
> funny characters inside it.
> 
> So I lost the hope to try to guess the password and I think to re 
> install Fedora.., but I have a problem.
> 
> My computer is dual boot with Windows XP and I am not sure how
> uninstall Grub (how to manage the MBR when to the computer start)
> before to uninstall Fedora... Some time ago I tried to fix this
> problem using Windows in recovery mode (command fixboot) and, at
> last, I had to reinstall also Windows XP (further that Fedora)..
> 
> Can I have an advice how  to arrange the dual boot on my computer, 
> before to uninstall Fedora??
> 
> Thank you regards
> 
> Angelo
> 
> 
> 
Hi you do not have to reinstall Fedora to reset the super user or root
account password. You need to boot into single user mode then type
passwd at the prompt then enter a new password.

Here are the instructions for single user mode:
<http://docs.fedoraproject.org/en-US/Fedora/13/html/Installation_Guide/s1-rescuemode-booting-single.html>