Suddenly cannot print on new format--why?

Have been using Pages quite a bit recently without problem. Suddenly, today, I cannot enter anything on a new blank format. If I pull up and old document, I can correct, enter more text, etc in a normal way, yet, not on a blank format. Additionally, the thumbnail option has started to appear with each new blank format requested and must be turned off each time. What has happened? i Mac with OS 10.8.5; Pages 09; 4.3