after Module deactivation: page not found

Hi there,

I try to update my 5.2 to 5.7. As explained in the upgrade.txt i disabled the contributed modules.
But now I get a 'page not found' error and cannot do anything in the backend any more (like switching to a core theme), or activating the modules again.
I am completely locked out.
I have the feeling that the views module was the last one i deactivated. Is there a possibility to activate the module again from the database (if yes how do I do that?). What is going wrong there
Quick help really appreciated.

thanks a lot