recovering overwritten folder....please help!!

Greetings all,
I have a client that had an issue with a folder on her server and it turned out it was a Microsoft message that said the computer had recovered from a serious error.....ok....fine.
Well she said her shared documents folder had disappeared and called me to come by to help. I went by after work and looked at it but it appeared she took a (windows) backup that I made a few weeks on an external drive ago and wrote that backup back to the shared directory and wrote over everything on the server.......so now it has all the data from a few weeks ago. I'm in the process of getting her set up on an offsite solution and now this happens.
Is there any way to restore this back to the original data? I am doing a scan of the HD with some software looking for deleted files, but not sure this would follow the same protocol as restoring overwritten files/folders...I just want to roll back the restore she did.

any help would be greatly appreciated!!!!!

Thanks in advance....

Mike

 

A little more info......the "server" is an XP Pro machine and the folder was shared .....the external drive is a USB HD.

 

Unless I'm missing something here, in my view, the only way a backup restore could overwrite anything else in a folder would have been if the overwritten file was also a backup file. If she purposely deleted the files in that folder, are they by any chance still sitting in System Volume for rstrui to find or the Recycle bin?

By the by - yes, this is my first post but I do have a certain amount of experience. :-D