The following guideline will help you to reset your vBulletin administrator in an event when “Forgot password” doesn’t work for you:
 Browse your forum and log out (if you have logged in using other user) if you aren’t already. Register as a new user and login as this user.
 In the vBulletin’s .zip file you can find a directory called ‘do_not_upload/‘. Inside this directory, there is a file called ‘tools.php‘. Upload this file into your forum’s admincp/ directory. Then go to the admincp/tools.php with your browser.
 At the bottom of the tools page is an option to ‘Reset Admin Access‘. Run it with the just newly registered username.
 You have just made yourself admin and you need this because you should now login to the admincp/ and find the user who’s password you have lost. Search for this user and when found you will see the whole profile including a password field. Set a new password.
 Go to the main forum and log out from the new user, and try to login with the old admin account. This should work now.
 When it works, go back into the admin control panel and find the newly registered user. The profile page will have a drop down in the top, from there select delete and delete the temporary admin.
 Then delete the tools.php file from your web hosting account. It is a potential security risk if you leave it on the web site.
The above steps will help you to reset admin password for vBlletin 3.x version.
If you have any questions related to vBulletin, just ask your questions in our webmaster forum.