Unable to open Encrypted Files in XP after Reinstall

Dear friends
I have some files in my one partition F: which are encrypted by the methods of Windows XP. To encrypt data: "Right-click on any folder and choose advance and click encrypt contents to secure Data". I have some problem with Windows XP, which is installed on C: Partition. I decided to format the partition C:. But after reinstalling Windows, when i try to open, move or copy the encrypted files, I got the error "Access Denied: file is encrypted or read only, unable to decrypt". I have tried "Elcomsoft EFS Data Recovery" but unable to decrypt the files.
Thank you
