Windows 7: HELP! Recovering encrypted files after rebuild

O/S: Win 7 Ultimate

I encryped a file share using the Properties "Encrypt this folder. . . " checkbox. I copied the folder and it's files to a USB drive as a backup (not an MSBackup, just a drag-n-drop copy).

I have since had to rebuild my system. I reinstalled the same Win 7 system, on the same computer, using the same user and computer name.

I now cannot do anything with the files or folders on the USB drive - cannot open, copy or delete the files.

Obviously the security token associated with the new user account has changed. Any suggestions?

The data is lost without a recovery key being made prior.
That is how encryption works.