EXCEL workbook is off-white, goes white in edit mode
 

I have ECXEL2000.
One workbook is normally slightly off-white as background colour.
1 How do I change that background colour ?
2 When in editing mode, the cells that change data all turn bright white
automatically. How can I control that interesting feature ? It does happen
in all my other files, but I would like to introduce it there.
Tx Joe