I have read many articles and talked to some data recovery experts about this problem. Sorrily my data is lost for ever!!!
The EFS (Encrypting File System) uses a private key to decrypt encrypted files. To decrypt these file, i MUST have the private key.
Windows XP allows the user to take a backup from EFS key information and user can store these information i a removable media (USB memory, Floppy disk, CD, ...). It is highly recommended that create a backup of your key when you use EFS.
If the user account or Windows installation is deleted, the key information could not be recovered. There is no way to recover key information after format.