Help im about to loose all my work on 250GB

[reveiled]

I have this external Lacie HDD 250GB (formated MAC OSX)
LAst night I used it to backup some files (pics and mp3) from my VAIO PC before reinstalling windows XP.
After backing up the files I restarted the PC and inserted the XP CD without disconnecting my Lacie HDD.
Now when ready to install XP I unmounted the partition of my Lacie HDD instead of the internal drive where i wanted XP to be installed. (I DID NOT FORMAT IT)
Is there anyway to recover all my data?
HELP!!!!!

 

[Lemon13]

http://www.filetransit.com/view.php?id=30909

http://software.techrepublic.com.com/download.aspx?docid=251206

hope this helps