Thank you for taking the time to report this issue and helping to make
Ubuntu better. Examining the information you have given us, this does
not appear to be a bug report so we are closing it and converting it to
a question in the support tracker. We understand the difficulties you
are facing, but
I need the authentication screen in order to use the synaptic package
manager and the ubuntu software which I can not access by now and I can
not install any new applications because they ask me for my password; I
can not send you any screenshots of the authentication pop up because it
is modal