A very bad menu bug

When ever i add a menu then level then build it reaches the menu and does this http://tinypic.com/view.php?pic=2yvnmgo&s=5
And then i can not do anything

It would look like you applied a texture/material for the buttons to make them different than regular GUI buttons… then u might have accidentally deleted some files which with no material to access causes the pink/purple color… how you fix this is by reapplying a new texture .