Windows 7: Windows Live Mail -- preventing user-created subfolder deletion

User accidently deletes user-created subfolders of Inbox in WLM causing loss of all email messages. Also, it is possible to accidentally drag-and-drop such user-created subfolders, which is not a good thing either. (I was surprised how easy it is to do this by mistake!) The "Inbox" itself cannot be deleted or moved by the user... but user-created subfolders can. I want to avoid time-consuming restores (which also results in loss of some of the email since backups are never up-to-the-minute.) Delete should be unvailable from Context menu. The subfolders should be undeletable just like the "Inbox" folder itself. Drag-and-drop should be disabled as well.
I have looked at file permissions (using both the Icacls DOS command and the Properties--Securtiy Tab permissions dialogue) but nothing has worked so far.
I noticed other similar complaints on the Internet, but most are concerned with how to recover the lost email. Unfortunately, I've already become an expert at this! I would like to prevent accidental deletions/moves completely if possible.
Any suggestions would be appreciated. Thanks!