@ dean535
Were there the code and pre tags like I had guessed from you screenshot. Can you post a screenshot showing what it looks like now and a screenshot of the edit page screen while in the visual editor. Do you have a page caching plugin or server caching? If you do, flush the cache. Also do a force refresh on your browser.
Or, better, yet… share a link to the page with me. My hands are pretty tied to what I can suggest by just looking at a picture … basically I’m guessing rather than giving your solutions.
Another thing you might want to look at. Open the page with Chrome, hit the F12 key and then click the Console tab. It appears there may be a fatal javascript error. These are usually always caused by other plugins. Most of the time the offending plugin can be identified by the file name and/or path given as part of the error.
Hope that helps!