hazelnut, Yes, thanks, I read the following article you posted:
Note: You cannot securely delete the ZIP file in Step 2 before you recover it. Recuva only creates the ZIP file when you choose to recover the emails.
So...I recovered it with Recuva and then tried to securely delete it with the overwrite feature on Recuva, but it still refused to wipe it. I also tried cipher from windows tool box, and itwould not get rid of Thunderbird emails.zip either.