Start menu is gone

I went to my sister's house tonight to install her printer and found that her start menu is gone.
The boxes that you pin to start, (that are suppose to be on the right side), are in the middle of the screen.
The start menu itself is gone. When I click on the windows icon to open the menu, nothing is there.
Instead, there are little lines in the upper left hand corner of the screen.

Also, the folders on the desktop have disappeared. (The recycle bin...documents, etc)
Can anyone tell me how to fix this problem?
I would appreciate any helped offered.
Thank you.