When you delete the installation directory, double check that you are actually deleting the right directory. Some people have deleted the wrong directory and they then get an error when trying to run Joomla because they have accidentally deleted files it needs to run.

If you’re installing 1.0.13, some people have had problems with being logged out of Joomla after they try to add new content, but then decide not to and cancel it.The Joomla developers are working on a fix for this, but in the meantime have suggested this change to the /administrator/index2.php file.

Whilst this fix hasn’t worked for everyone, and is only a work-around until they update the core files, it’s a good place to start if you’re having this problem.

BEFORE
 
 Code:
 103  doGzip();
 104 
 105  // if task action is ’save’ or ‘apply’ redo session check
 106  if ( $task == ’save’ || $task == ‘apply’ ) {
 107   $mainframe->initSessionAdmin( $option, ” );
 108  }
 
 change this to
 
 Code:
 102  // if task action is ’save’ or ‘apply’ redo session check
 103  if ( $task == ’save’ || $task == ‘apply’ ) {
 104   $mainframe->initSessionAdmin( $option, ” );
 105  }
 106  doGzip();
 
 
Whilst this problem affects windows servers more than apache, some people have reported it using apache servers.
You can read more about it here: http://forum.joomla.org/index.php/topic,193707.0.html

Also, make sure your cookies are enabled when you work in the backend of Joomla.
When configuring the configuration file, configuration.php, make sure you specify the right path name. In some hosting environments, instead of putting  /public_html  you may need to put  /home/myUsernam/public_html. The line this goes on is $mosConfig_absolute_path.

If you’re having problems with your site coming up with text only, but no formatting tables, or images or background colors, you could be having a problem with your settings. It’s likely you’ve used the incorrect settings in your configuration file. You need to use the full web address, so that the server can be recognized publicly (and not just where you’ve installed it locally).The line in question would be: $mosConfig_live_site = ‘yourdomain.xyz/yourdir/mambo’;You need to make sure the right directory, and subdirectory are specified (if you installed Joomla in a subdirectory. If you didn’t then you don’t need to worry about that part..