JAuthentication::__construct: Could not load authentication - Joomla! Forum - community, help and support

2 days ago suffered error on log in page:
"jauthentication::__construct: not load authentication libraries"
i had not altered or changed since last log in.

i unable log in , have been doing research on how correct issue since.
i have tried:
- changing enabled '1' in jos_extensions
- checked username type in jos_users "super administrator"
- tried backing plugins/authentication folder , replacing freshly downloaded one. no luck reverted original folder.
- have tried methods here: viewtopic.php?p=2562669

i'm @ loss here , desperately need save weeks of work. possibly help?

version 2.5.8

rickingham wrote:- changing enabled '1' in jos_extensions

we assume database prefix not jos_ make j1.5 site. when in "jos_"extensions did ensure both authentication_joomla , user_joomla set "1" - enabled?