Drush bootstrap level error Im running onto some issues with Drush. I worked with php 5.3 and after upgrading to 5.5, i ran into some issues and decided to downgrade my PHP version back to 5.3. Now im running into the issue that Drush isnt working anymore.

Command cache-clear needs a higher bootstrap level to run - you will need invoke drush from a more functional Drupal environment [error]
to run this command.
The drush command 'cc all' could not be executed.                                                                                [error]
Drush was not able to start (bootstrap) the Drupal database.                                                                     [error]
Hint: This error often occurs when Drush is trying to bootstrap a site that has not been installed or does not have a configured
database.

Drush was attempting to connect to : 
  Drupal version    : 7.28
  Site URI          : http://default
  Database driver   : mysql
  Database hostname : 127.0.0.1
  Database username : root
  Database name     : drupal_practice2
  Default theme     : garland
  Administration theme: garland
  PHP configuration : 
  Drush version     : 4.5
  Drush configuration: 
  Drush alias files : 
  Drupal root       : /var/www/drupal
  Site path         : sites/default
  Modules path      : sites/all/modules
  Themes path       : sites/all/themes
  File directory path: sites/default/files
  %paths            : Array

You can select another site with a working database setup by specifying the URI to use with the --uri parameter on the command
line or $options['uri'] in your drushrc.php file.


Ive been searching on google for almost 3 days now and re-installing my computer would be a lot faster. I have lots of data so i dont want to re-install.

Someone that can help me with the solution?
Your problem is that Drush is running the PHP version that you have installed for your hosting environment (and Drush's own php.ini). You need to get Drush to run its own PHP that it installs with. 

What host are you running on? If it is Windows then open a console and type set. That will show you the environment variables that you are using for your account. If there is a PHP variable in there, note it's contents and delete it by issuing the following command in the command windows: set PHP=

If that doesn't work set it back to what is was before. Any other platform I cannot help you with.

Also check this post: Modifying the PHP or PHP configuration that drush runs under