CTRL + F5 will just refresh the browser cache. The problem could be the server-based cache and Quick Cache could cause the issue, especially if it modifies .htaccess (it at least relies upon it for gzip) to do the caching (this would mean that even if the module is disabled, the caching could still happen if the rules are left in .htaccess).
Without access to you .htaccess, Wordpress install or server logs, it's not simple to diagnose, JakoJJ. Several things could cause a fail. It could be as simple as saving the permalink settings again. (I'm not saying that would fix it, but something at this level has gone wrong.)