How do you go about access windows API's

Find a decent tutorial on them - try FunctionX.

Use ANY compiler that supports writing code for windows (can read windows header files and link windows libraries).

Than you include the required files for each API function you wish to use and simple use that function. Certain functions will also require linking specific libraries, you can figure out which files and libraries, as well as a list of Windows API functions that are available through http://msdn.microsoft.com

Good luck.

check MSDN

and as a hint , you must use the :

winuser.h
and
windows.h

libraries

good luck

and if you want to ask about a specific API feel free to ask about it