Vista - How about Excel preview handler

In my computer, when you preview a office 2007 document, the preview handler works as it should; giving me a nice preview of the file I want to view. When I open Word and use the open file icon and search for a word doc, it will preview the file as it should. Now here is my problem. When I launch Excel or PowerPoint and use the same method of previewing a file as word, the file will not preview at all. If I change the file types to all and open a word doc, its will preview just fine. Also if I preview an Excel file through windows explorer, and then open Excel and preview a file by the open file icon it works as it should also. I was wondering if this is a bug with the office system and if there is a fix for this behavior. I am using Vista Ultimate X64.