“Find” won’t find on XP Home pc

I wanted to find the .pst file for my Outlook so I could back it up to a CD, so, on my XP Home edition PC with indexing enabled, I went to the Find utility and typed in *.pst. Under Advanced options I selected to search hidden and system files. 0 files found. I know I have a couple of .pst files – why would this simple (at least it used to be) utility fail to find them? Anybody?