For admin,.. step by step instructions for FIXING the forum:
1. Backup the existing forum
2. install the latest smf software in a different location on the server
3. Initialise the new (blank) installation and check all functions are working (some default path settings may need tweaking)
4. Update the style sheets to include the header image & advertising from the old installation
5. Copy the members, category's, boards, messages etc from the old installation to the new one
6. Run the maintenance functions in the admin centre and check all settings (PMs disabled) etc are set as you wish
7. Re-instate any specific member category's & check mods etc have retained their privileges
8. Once you're sure everything is working, modify the index.php file in the old forum to auto-forward everyone to the new forum installation,.. the forum will continue to function seamlessly throughout the process.
9. Thank me for the awesome advice & reward me with free advertising for life.