How to Close a Window

[iamnew]

A window popped up which says " None of your preferred networks are available".

There is no option to close the window like there normally is in the upper right or sometimes lift corner. I can not type in that window or right/left click in that window does nothing. The only thing I can do is move that window. However it will not go into the trash.

How can I get it off? Thank you to anyone who can help me out.

 

[S.B.G]

Try using Force Quit from the menu in the upper left and see if there is an application that corresponds to this window.

 

[Ronald Williams]

press command - option - escape simultaneously then select the application you want to force quit from the force quit applications window that pops up, select the program that you want to force quit then click the button that says force quit.