When installing DRUPAL, after configuring database name, login, password, host, port and prefix, you will be redirected to another step. In this new installation step you will be asked to Configure Site.
You will have to configure the Server settings section. There you will find the option to make clean urls. If you have installed wamp by default you will not have the chance to enable clean url’s.
How to solve this issue? Just go to your wamp control panel, menu Apache -> Apache modules and click rewrite_module. Now just update your Drupal installation web page and you will be able to enable clean urls.
Hope it helps someone 