When I try to add or edit a product I receive the following error:

Mage registry key "_singleton/weee/observer" already exists

Trace:
#0 /data/websiteaddress.com/htdocs/app/Mage.php(222): Mage::throwException('Mage registry k...')
#1 /data/websiteaddress.com/htdocs/app/Mage.php(476): Mage::register('_singleton/weee...', false)
#2 /data/websiteaddress.com/htdocs/app/code/core/Mage/Core/Model/App.php(1316): Mage::getSingleton('weee/observer')
#3 /data/websiteaddress.com/htdocs/app/Mage.php(447): Mage_Core_Model_App->dispatchEvent('adminhtml_catal...', Array)
#4 /data/websiteaddress.com/htdocs/app/code/core/Mage/Adminhtml/Block/Catalog/Product/Edit/Tab/Attributes.php(143): Mage::dispatchEvent('adminhtml_catal...', Array)
#5 /data/websiteaddress.com/htdocs/app/code/core/Mage/Adminhtml/Block/Widget/Form.php(144): Mage_Adminhtml_Block_Catalog_Product_Edit_Tab_Attributes->_prepareForm()
#6 /data/websiteaddress.com/htdocs/app/code/core/Mage/Core/Block/Abstract.php(862): Mage_Adminhtml_Block_Widget_Form->_beforeToHtml()
#7 /data/websiteaddress.com/htdocs/app/code/core/Mage/Adminhtml/Block/Catalog/Product/Edit/Tabs.php(79): Mage_Core_Block_Abstract->toHtml()
#8 /data/websiteaddress.com/htdocs/app/code/core/Mage/Core/Block/Abstract.php(238): Mage_Adminhtml_Block_Catalog_Product_Edit_Tabs->_prepareLayout()
#9 /data/websiteaddress.com/htdocs/app/code/core/Mage/Core/Model/Layout.php(456): Mage_Core_Block_Abstract->setLayout(Object(Mage_Core_Model_Layout))
#10 /data/websiteaddress.com/htdocs/app/code/core/Mage/Core/Model/Layout.php(472): Mage_Core_Model_Layout->createBlock('adminhtml/catal...', 'product_tabs')
#11 /data/websiteaddress.com/htdocs/app/code/core/Mage/Core/Model/Layout.php(239): Mage_Core_Model_Layout->addBlock('adminhtml/catal...', 'product_tabs')
#12 /data/websiteaddress.com/htdocs/app/code/core/Mage/Core/Model/Layout.php(205): Mage_Core_Model_Layout->_generateBlock(Object(Mage_Core_Model_Layout_Element), Object(Mage_Core_Model_Layout_Element))
#13 /data/websiteaddress.com/htdocs/app/code/core/Mage/Core/Model/Layout.php(210): Mage_Core_Model_Layout->generateBlocks(Object(Mage_Core_Model_Layout_Element))
#14 /data/websiteaddress.com/htdocs/app/code/core/Mage/Core/Controller/Varien/Action.php(344): Mage_Core_Model_Layout->generateBlocks()
#15 /data/websiteaddress.com/htdocs/app/code/core/Mage/Core/Controller/Varien/Action.php(269): Mage_Core_Controller_Varien_Action->generateLayoutBlocks()
#16 /data/websiteaddress.com/htdocs/app/code/core/Mage/Adminhtml/Controller/Action.php(275): Mage_Core_Controller_Varien_Action->loadLayout(Array, true, true)
#17 /data/websiteaddress.com/htdocs/app/code/core/Mage/Adminhtml/controllers/Catalog/ProductController.php(207): Mage_Adminhtml_Controller_Action->loadLayout(Array)
#18 /data/websiteaddress.com/htdocs/app/code/core/Mage/Core/Controller/Varien/Action.php(419): Mage_Adminhtml_Catalog_ProductController->newAction()
#19 /data/websiteaddress.com/htdocs/app/code/core/Mage/Core/Controller/Varien/Router/Standard.php(250): Mage_Core_Controller_Varien_Action->dispatch('new')
#20 /data/websiteaddress.com/htdocs/app/code/core/Mage/Core/Controller/Varien/Front.php(176): Mage_Core_Controller_Varien_Router_Standard->match(Object(Mage_Core_Controller_Request_Http))
#21 /data/websiteaddress.com/htdocs/app/code/core/Mage/Core/Model/App.php(354): Mage_Core_Controller_Varien_Front->dispatch()
#22 /data/websiteaddress.com/htdocs/app/Mage.php(683): Mage_Core_Model_App->run(Array)
#23 /data/websiteaddress.com/htdocs/index.php(124): Mage::run('catalog', 'website')
#24 {main}

Magento ver. 1.7.0.0
Compiler turned off
cleared cache
rebuilt index
no updates or new extensions have been installed it just quit working

Any help would be appreciated!