How to Re-Install Joomla
If for some reason Joomla needs to be re-installed, you should make sure that you have taken measures to keep data backed up. This is important, because when re-installing Joomla, all data is lost. By creating a backup before re-installing you will ensure that you will not lose any time due to some unexpected issue and will be able to quickly revert your website to old version, when your Joomla site did not have any problems.
Backup can be easily done by using the built-in backup feature in the hosting account control panel. For example, in DirectAdmin, a backup can be created by going to “Create/Restore Backups”.
If you are using cPanel, a backup can be created by clicking on either “Backups” or “Backup Wizard” as shown below.
Once the backup is done and safely placed, you can start re-installing Joomla. The first thing you should do is get the same Joomla version as the one your current website is running. You can download it from the official Joomla website.
Go to the current Joomla installation folder and rename that directory. You can do this by using the built-in file manager in your hosting account control panel or simply an FTP client.
Then, create a new directory for the domain name in the same place as the renamed directory. This step can be completed by using the same utilities as in the previous step.
Upload the new Joomla copy to the newly created directory. It is usually best to use FTP for uploading files with login details obtained from a hosting service provider.
Now it is time to launch the Joomla installation by opening the domain name in which you are re-installing. Simply open a web browser and enter the domain name, for example, domain.com/joomla_directory if you have files uploaded in this directory. An additional path is not required if the files are placed in the public_html directory.
Follow the installation steps in order to get it installed and enabled. Make sure to choose a new database for the installation as well.
Download and install the extensions and templates that you have been using before. In this step, we would also recommend to copy the content and other required data like images, videos, etc. from the previous website.
Finally, if everything is was done correctly, you should have re-installed your Joomla website successfully. If you have any issues, you can always roll back to the backup, created before reinstalling.