Left menu pane vanished

[SpanishRed]

The lefthand menu pane of my software vanished while I was busy working with GIMP, so clearly I pushed something I should not have pushed. I've tried: 

• Pushing tab
  
• Cnt B
  
• Looking for an option in the "View" menu
  
• Looking for an option in the "windows" menu. 
  

Nothing works. Then I tried uninstalling and reinstalling the software, but it won't uninstall. I've tried uninstalling from the apps and features menu as well as from the start menu.