Email has an attachment. You delete email. Email is gone.
BUT
Attachment has been downloaded to whatever file you have told your browser to download to.

If your virus scan catches it and you use it to delete email, attachment will be deleted also.

If you delete email on your own, then attachment stays on your hard drive, until you go into file and delete it.

How many jpg chip scans have you recieved via email attachments? I bet you have deleted many of the emails thay came in on, but the jpg's are still in your download file. You could go in the file and double click any one and open it. Same for an attached exe file.

I am sure someone one post if I am wrong.