vBulletin Mods

i have an interesing question is there any way to ban the admin of the site???if not then can it happen???

No, you can't ban the founder account, due to the fact that the account will have been protected from such a thing.

The only way to ban admins is to demote them, then ban. Protected admins should be unprotected, demoted, then banned.

how to unprotect them???

Go into your Host's control panel, access the file manager, then go to the includes/config.php file (or /forum/includes/config.php). Edit config.php

Search the document for "Undeletable / Unalterable Users"
and remove the userid of the specified user from between the ' ' tags.