Some time that may happened that some text you are changing from right file and is not reflecting to the site. Like registration page, login page, onepage login page or onepage billing. So below is a solution for such things.
Actually all above things are Persistent Files which will not going to change from normal files you can find from customer folder or checkout folder. To find such files go to:
For login & registration file :
For onepage login and billing:
Magento acquire this feature from Magento Community 1.6 version.
Because this feature preserves information about customers using a long-term cookie. Once a customer logs in to a site, a long-term cookie is established for that browser/device combination. So the customer is able to view the contents of their shopping cart in subsequent sessions without logging in again.
Hope it helps!