Question : how to delete or call back an email sent to all users

I would like to know how to delete or recall a email that was sent to all users that has an attachment? Is there a way this can be done from the server end? If I delete the end users email account account will this delete all the unread email? there has been some people that have opened the email and opened the attachment
I have about 150 accounts on exchange 2003. What are my options for fixing this problem?
I would like to thank you for taking your time in reviewing this question and I look forward to any and all help

Answer : how to delete or call back an email sent to all users

Message recall doesn't work. You will get about 60% success rate, if that.
If the message is identical then you can use exmerge to remove the message from the store, which will be more reliable than recall.

Simon.