Windows Vista login failure. security option error

Hi all, recently im very frustrated with the above-mentioned error.

im running windows vista 32 bit (home premium) since last year. and only begins to receive this kind of error this week.

as spread across the net, basically, i tried to login to windows, after inserting password / fingerprint / face recognition, it says loading, longer than usual. and nothing comes out. black screen. i tried ctrl-alt-del but it says security options fail or sth like that...

i tried searching google for that, but no visible "cure" were found.
3 days ago, i just cleanup my system and it just gave this error. which doesnt allow me to system restore. which means, i need to "recover"

today, im getting the same error again. only i can do system restore. the strange thing today is, it says updating windows, despite i've turned off all windows update.



so my question is: why am i getting this?
before the incident 3 days ago, i've never encounter such a problem.
and, basically i did not mess with the reg or sys files...