You need to run static content depolyment comment in your server.
Use the following comment
php bin/magento setup:static-content:deploy
Clear cache and set correct folder permission
OR
When Magento 2 is not in production mode, it will try to create symlinks for some static resources on local server. We have to change that behavior of Magento 2 by going to edit ROOT > app > etc > di.xml file. Open up di.xml in your favorite code editor, find the virtualType name="developerMaterialization" section. In that section below, you will find an item which needs to be modified. You can modify it by changing the following content:
Magento\Framework\App\View\Asset\MaterializationStrategy\Symlink
To:
Magento\Framework\App\View\Asset\MaterializationStrategy\Copy
Now last step, also delete old files generated in ROOT > pub > static > DELETE ALL EXCEPT .HTACCESS