Try this Before that take Backup

Remove everything, except .htaccess file from pub/static folder

Open up app/etc/di.xml find the path “Magento\Framework\App\View\Asset\MaterializationStrategy\Symlink” and replace to

Magento\Framework\App\View\Asset\MaterializationStrategy\Copy

Note: Remove entire files and folder under pub/static except .htaccess file.

For More info ref this http://www.dckap.com/blog/magento-2-admin-links-not-working-in-windows/

Other Solution

You can run below command from the Magento root folder.

 php bin/magento setup:static-content:deploy 

This will download the content perfectly in respective folders.