Outlook 2007 Page Format Changed

A couple of days ago the appearance of my Outlook 2007 page changed. I used to have a column on the left which had Inbox, Sent Items, Deleted Items, Drafts, etc. in a section on the top and then a scroll down list of my personal folders. Now everything is merged into Personal Folders and another column opens up with the content of the selected file, leaving little room to view the file in a third pane.
I don't think I made these changes....what happened and how do I get my old format back?
I read that sometimes Outlook gets corrupted and needs to be reloaded; I did this and it took me a bunch of hours to find my files and contacts which were in hidden files to reload.