As a good Siteowner you should always make regular BACKUPS
of your DATABASE
before installing any mod
Dont Know how to backup your Database? READ= How to Backup and Restore your website database Using control panel
Some Admins Just install Mods without Backing up their Website, And the mod destroys the Entire Forum. WELL RELAX YOU MIGHT JUST BE LUCKY
SMF being a nice helpful system takes backups for you, the only issue is when you restore the backup it takes you back to the last mod you installed (You CAN use it to restore older mods, by going through the files in reverse date order)
FOLLOW THE BELOW STEPS
Login to your site Directories using Filezilla or any FTP program
Goto the PACKAGES
In there you will find another directory named BACKUPS
Now let's assume, for the sake of this tutorial, that the last mod that you installed was "PM On Registration".
You will need to locate something like this in the Backups directory "2010-01-26_before_PM_On_Registration_1-0-2.tar.gz"
The numbers at the front of the filename is the date that the mod was installed, So yours should be different.
Download that file to your desktop, or somewhere fairly empty of files and dearchive it.
It's a "gz" file.
When you dearchive it you'll be left with a "tar" file.
If you dearchive that, you'll find loads of files and directories.
Upload those files and directories to your forum, overwriting what's there, now. (It'll take a while).
When that's done, Voila! Your forum should be exactly as it was, before you installed the mod!
Next time, backup before installing mods, won't you?
If you have any questions Post below