Overwritten .pst files

I recently used a tool from MS to migrate files and user settings from one computer to another computer. problem is I was trying to send files from Bcomputer (with Vista operating system) to Acomputer (with Fresh install of XP both with office 2007). I think the link was sending "A" to "B" as you would normally upgrade, not go backwards. B/C "A" was fresh install when I went opened the "B" computer there is no email, no folders, nothing. I did manage to find the .nk2 file and that is still in tact, my question is simply this, have I lost all old email or can it be found somewhere?? I tried a system restore but to no avail. I did a search for .pst file but only came up with a file that shows modified approximately the same time I tried to transfer.
Any help or suggestions would be appreciated.
Thanks Steve

Not sure what this has to do with Outlook, but it sounds like you found your .pst file?

Have not found the origional .pst, the one I found is only 277KB in size hardly several years worth of collected emails.
I am currently using a DATA recovery disc to see if I can find them, still no luck thus far. I am afraid that Windows EZ transfer blew them away