title: Mage registry key "_singleton/core/resource" already exists
body: <pre><code>Mage registry key "_singleton/core/resource" already exists
  </code></pre>
  
  <p>Trace:</p>
  
  <pre><code>#0 /home/sourceciti/public_html/demo/nrrexports/demo/app/Mage.php(223): Mage::throwException('Mage registry k...')
  #1 /home/sourceciti/public_html/demo/nrrexports/demo/app/Mage.php(477): Mage::register('_singleton/core...', Object(Mage_Core_Model_Resource))
  #2 /home/sourceciti/public_html/demo/nrrexports/demo/app/code/core/Mage/Core/Model/Resource/Setup.php(141): Mage::getSingleton('core/resource')
  #3 /home/sourceciti/public_html/demo/nrrexports/demo/app/code/core/Mage/Core/Model/Resource/Setup.php(234): Mage_Core_Model_Resource_Setup-&gt;__construct('core_setup')
  #4 /home/sourceciti/public_html/demo/nrrexports/demo/app/code/core/Mage/Core/Model/App.php(417): Mage_Core_Model_Resource_Setup::applyAllUpdates()
  #5 /home/sourceciti/public_html/demo/nrrexports/demo/app/code/core/Mage/Core/Model/App.php(343): Mage_Core_Model_App-&gt;_initModules()
  #6 /home/sourceciti/public_html/demo/nrrexports/demo/app/Mage.php(684): Mage_Core_Model_App-&gt;run(Array)
  #7 /home/sourceciti/public_html/demo/nrrexports/demo/index.php(87): Mage::run('', 'store')
  #8 {main}
  </code></pre>
  
  <p>hello guys am getting this error,and all my design has gone,please help me how to solve this,please guys</p>