How to restore/retrieve lost Outlook Express email files/folders?

I was in Outlook Express reading emails and then sorting them to my various saved folders on my only computer. The battery back-up beeped, shutting down the computer and the system. When I turned the computer back on, I discovered that I lost all the saved files/folders and my sent emails. The Inbox and Address book was still intact. Is there any way to restore/retrieve the lost/deleted(?) files/folders and sent emails. I'm more concerned with getting back the saved files/folders than the sent emails. My internet server is Charter which I have questioned them to no avail. What about the System Restore function? Any help, support, suggestions would be appreciated. Are they any software programs that are safe to use without corrupting my entire system?