I want to only display visits to my site which were sent by my Google Adwords campain preferably in the Visitors overview page.

I've tried filtering with 'Advanced Segments' but when I select "Paid Search Traffic" visits goes down to zero. But I do know that most of my visitors at the moment are being sent from Google Adwords.

In this question the answer (which was not chosen) suggested adding a HTTP GET request or an URL shortener, but surly there is a way to do it in Analytics?