New posts won't preview

I have been trying to upload a post but when I go to preview it I get the title and the comment box but no post. I’ve tried doing it a number of ways but it won’t preview. I have had problems in the past with my permalinks. Is this a permalink issue?

I’m a newbie when it comes to wordpress. Is it possible to change the permalink structure? I know that it can be changed in the control panel but will that mess up a site that has many posts going back several years or will it only change the permalinks from the time I change it onward? Or could it be another issue that I am not aware of?

If I go to preview the post with no “name” in the title field, I can preview. If I add a name then the permalink changes accordingly and then I have the “no preview” issue. Thanks in advance. Woody