Log in to your vBulletin admin control panel.
If you have a vBulletin forum, you might eventually have a user that wants to delete her account. She may want to delete her account to start a new one or to leave your forum completely. Individual users can't delete their own accounts, so a board administrator will have to do it.
Click the "Users" menu and then "Search for Users."
Type the user's screen name and click "Find." You can also click "Show All Users" and scroll through the list to find the account to delete.
Click the drop-down menu to the right of the user's name and click "Delete User."
Click "Yes" to confirm that you want to delete the account.