application data files

The application data file is missing. As a result my
email msft outlook is messed up. My outlook has generated
3 filders of files and i dont want them all. I wish to
restore the .pst files but not thru backup because the
computer has backed up the bad configutation and i simply
want to delete the .pst files that are there now and copy
in the files I want.

If a solution is to reinstall window xp, can Iselcet the
upgrade option so Iwont lose my data.