Question about Outlook Express

I inadvertently deleted them while trying to remove a file I didn't recognise.  I got them back for short time using "Go to" but they disappeared again.  I went to C:\Users\user name etc. searched and found the folder and sub-folders but they were all empty.  Does this mean that I have lose these imortant stored files forever? I really need some that are very important and I am devastated.