New emails disappear

I am beside myself with this issue and request help from the Community.

I have a client running Windows 7 - he uses Windows Essentials 2011 - the email part of it as an email client.

For no reason at all it suddenly will not place messages received in the Inbox. The messages flashes for a brief moment as if it is being placed in the inbox then disappears from sight. Its not in the Junk folder and its not in the deleted items folder. Its NOWHERE !

I have tried:

Restoring the system to an earlier date.

Repairing Live Essentials using the Repair Utility.

Uninstalling and resinstalling the program.

Deleting the users inbox using Windows Explorer and drilling down to the store folder.

Deleting the account and recreating the account.

ANY and ALL assistance is greatly appreciated.

Thank you

Cornerstone LLC

Original title: Windows live mail 2011 issue - received message flashes for a moment then is gone !