The 'main' company record view no longer appears. The database is still there, and sortable, but I can only view the information in the secondary tabs. The primary page with all the most pertinent company information seems to have completely disappeared. I don't know how to get it back!
Turns out that you can pull the window down from the top (as you would in Excel). Somehow, my main window had gotten all screwed up and was only showing the bottom section of the page. It's fixed (although the layout is completely different now due to all my futzing around in there....), but all the data is there!