Main Outlook Window Just DIsappeared

Hi:

Weird. My main Outlook Window just disappeared. That is, I cannot access my inbox, folders, etc. since the window where all these items normally appears is nowhere to be found. Outlook seems to launch normally, but the main window has gone on a walkabout somewhere.

When I click on the yellow Outlook icon in the Dock I get the Outlook menu bar at the top of the screen (Apple Menu, Outlook, File, Edit, View, Message, Format, Tools, Window, Help, Apple Scripts).

File > New > E-Mail Message brings up the compose window box and I can successfully send a message from here.

So where did the main window go???

Outlook runs well on my work computer and my portable MBP, all of which have similar software setups. This issue just occurs on our home iMac.

The last thing that happened in Outlook when it was working was a window asking to upgrade Microsoft Silverlight. I have no idea what Silverlight does, but since it was from Microsoft I installed it and all seemed to go well. I have no idea if this is the issue or not, but it was a bit odd so it caught my eye.

OS 10.10.3

Office for Mac 2011 14.5.0  

Any advice to get Outlook for Mac 2011 back working normally again would be really great; I totally depend upon this program.

Thank you!!!