If we don't follow backup and restore instructions such as http://support.microsoft.com/default.aspx?kbid=196492 then we must test ahead of time what happens when we make it up ourselves.
Hopefully the article can help you find your missing items.
I have a large PST file made from the Outlook 2000 export tool. I imported it after I made a clean install of XP and Office. I do not have any of my folders that I made. The default folders show, but not any of my custom folders where I stored mail. I backed up my Personal folder with all subfolders. The file is quite large, so I am quite sure the data is there. Any idea how to get it back?