Which mail program are you using to send your e-mail? You mentioned MSN, but also having a stuck outbox which sounds more like an Outlook Express issue. If you are using the MSN webmail have you checked your sent items folder? Pictures attached to email in the sent items folder are viewable at the original size.
Did you upload any of the pictures to web sites such as MySpace or Facebook? Do you use any online photo album sites that may have some of the originals?
I understand it may be too late, but now is a good time to add an external hard drive, internet backup, CDRW, or other backup option to your computer so you can backup the files that are important to you and not have a repeat of this problem.
What exactly happened when your hard drive broke? Did Windows get reinstalled? Did you put in a new hard drive? The less you do on the computer and the more details you can give the better the chance that some of the files can be recovered. Big Dan is more of a Windows expert than I am, so I hope he has some good recommendations for you about programs that you can download that will help you to recover the lost files.