VERY lost .pst files

My husband's computer received a "cyclic redundancy error" in Outlook. I
performed, I though, all the necessary procedures to repair the problems
(backed up Outlook, chkdsk, Inbox Recovery tool, etc.). However, when I
backed up Outlook, I must have erroneously backed up a previous Outlook file
from two years ago. His current contacts, calendar -- all current .pst files
-- are gone. The files WERE there before I repaired the problem (he just
couldn't send, receive or delete email). I performed a search, including
hidden .pst files, and did not locate the updated .pst files. Any other
ideas as to where I could look, or are we just screwed?
--
Doods