All extensions are disabled from the admin panel and the admin panel is empty.
How to enable it again?
app/etc/modules all are set as active=true
So is there a way to enable it from the database?
You can directly enable it from database if its already enabled it from module xmls.
Goto core_config_data and search run the below query:
SELECT * FROM `core_config_data` WHERE `path` LIKE '%advanced/modules_disable_output%'
This will returns all the modules enabled or disabled from admin. If value is 0 then its enabled and if value is 1 then its disabled. You can change the values according to your requirement.
Delete the cache and session directory from var directory and test if everything works.
Hope this helps!