I appear to have lost all my Emails stored in my Windows Live Mail 2011 Storage Folders.

I  now Windows 7 and my full Emails were transferred from my earlier Vista system. All worked well for a long time until a few days ago when I  attempted to set up a new 'message rule' for a particular 'sender' whose junk Emails continued to arrive in my inbox despite blocking the sender and his domain. I am not sure of the sequence of events that took place whilst in the 'message rule' set up in Folders but it looks like I left all the named storage folders in place but all the contents have gone. Any help would be appreciated !!