Data Recovery

hellow every1 thnks for your support, i’ll start with my problem right away, recently i formatted my IBM server which was running on win2000 adv. server & installed win2003 std. server wiht raid5, but i have lost some of my data, though i had backed everythin there are some file which i forgot to take backup, now is there any way I can retrieve my data, any free tool that can help me out new server is working fine, but is it possible to retrive the data from formatted disk
pls ignore the points as i didn,t much left with me.
Thnks once again for your support