How To Terminate a Running Code without exiting the program in MFC with visual studio

Hi Everybody
i am using visual Studio 2010 and i have a GUI. i have a button named "Calibrate". when i press this button, a process starts that it takes 30 seconds. sometimes in the middle of this process i want to cancel it. but i dont want my GUI to get closed. so for example i need another button named "Stop Calibration" but i dont access my GUI when i press "Calibrate".
Does anybody have any idea how to handle this problem?
thank you all

Have a look at
http://flounder.com/workerthreads.htm
http://www.codeguru.com/cpp/cpp/cpp_...ead-Part-I.htm