I had a problem with Windows Live Mail where it would only show the header of the email and not show the text. The header had the text of the email as an attachment but did not display it in the box where it usually is shown.
I was able to correct it a few times by restarting Windows Live Mail or Windows, but eventually it would not correct itself.
After doing a search online, I found the solution. Here it is.
Go to Control Panel, Programs and Features.
Scroll down to Windows Live Essentials and double click on it.
When the windows opens, select Repair and click on the Continue button.
That should repair it.