missing files/folders

Vista Home Premium

As of Friday 2/6, I seem to have lost a number of files and folders.
By 'lost,' I mean the files are not visible in Explorer in ANY folder,
not visible in Recycle Bin, and not located by FIND. All these seem to
have just disappeared.
I made one significant change - deleting Norton Internet Security 2008
and reinstalling the NIS 2009. But, I am not certain what day that
occurred - Web, Thur, or Fri.
The missing files are varied - txt, idx, html, . . .
Folders in two different places are missing - so far. I am uncertain if
others vanished. Some of the files are on my backup but some are not.
I did NOT (intentionally) delete them but, even if I did, I would expect
to find them in Recycle Bin.
Any suggestions on how (if) I can locate these files?

There are a number of utilities to try to recover deleted files.
Files are never really gone unless the data has been written over, which may
have already happened.
I have had terrible experiences when uninstalling Symantec products over the
years, including entirely trashed hard drives--this could be you, or maybe
not.