[Lynne]

You may have to use tools.php to reset your access (although, the original symptoms sound very weird - I wonder if you have been hacked).

1. Download a copy of the vBulletin zip file from vBulletin.com (if you don't already have it).
2. Once you have done so, extract the contents and navigate to the do_not_upload folder, from this folder select the file named tools.php and upload this to your /admincp/ directory on your board (via. FTP).
3. Type in the path to the file in your address bar, e.g. http://www.yourboard.com/forums/admincp/tools.php
4. Enter the details required.
5. You will then be presented with a list of options, you'll need to look for one which says 'Reset Admin Access' and follow the on screen instructions.

Once this has been done, remove tools.php from your AdminCP folder.