use of Constructors and Static Keyword

The type of Constructor and their use are clearly defined over here  :

http://www.codeproject.com/Articles/7011/An-Intro-to-Constructors-in-C
The study of constructor leads me to the importance of Static classes, methods and variables, which was cleared from here :

http://www.codeproject.com/Articles/15269/Static-Keyword-Demystified

thanks.