After imaging the computer to the new version from Windows XP to
Windows XP 2003, I did not make copies of the PST files.  I lost all
the Microsoft Outlook files.  Please help me recover the files.

This data is very important to me.  Pls help me.

Imaging irrevocably erases anything that was on the Hard disk , hence
the word image! it writes the new data sector by sector or track by
track on the disk wiping everything

The only way to get data back would be a professional restoring
service but they will cost you a bundle (anywhere between 500 to 5000
U$ depending on the work that needs to be performed)

Sorry

brobles, I concur with corwin_02 but you can try a consumer-oriented
recovery analysis for free.  If it cannot recover your data, pay
nothing. If it thinks it can get that one PST file, then you pay the
actual recovery action.

Here is one such utility:
http://www.finaldata.us/

And here is another from the makers of diskeeper:

http://consumer.undelete.com/undelete/undelete.asp?RId=1&SId=2&CId=13