Clena url not working properly

Hello, I'm having a big problem with my website and I will need help.
I have clean url on my drupal site and everything was great until I notice drupal wasn't displaying in browser the right url, it was displaying www.example.com/node/44 and it was supposed to have www.example.com/about. It just not working with some urls/nodes
In 'input format' it have the right name but drupal doesn't apply it.

I don't know if have any think to do it but this node have another sub-page attacked. and the node is not showing -also- the sub page. Everytime I selected the sub-page I want to be displayed there I save it but drupal deselected it automatic and I get nothing. Nothing on browser (clean url) and nothing on my view...
One day my site was fine on the other day I notice this... Can anyone help me????? Please????

I'm really losing my hopes about drupal....