import ctypes
MOUSEEVENTF_MOVE = 0x0001 # mouse move
MOUSEEVENTF_ABSOLUTE = 0x8000 # absolute move
MOUSEEVENTF_MOVEABS = MOUSEEVENTF_MOVE + MOUSEEVENTF_ABSOLUTE

MOUSEEVENTF_LEFTDOWN = 0x0002 # left button down
MOUSEEVENTF_LEFTUP = 0x0004 # left button up
MOUSEEVENTF_CLICK = MOUSEEVENTF_LEFTDOWN + MOUSEEVENTF_LEFTUP

def click(x, y):
    x = 65536L * x / ctypes.windll.user32.GetSystemMetrics(0) + 1
    y = 65536L * y / ctypes.windll.user32.GetSystemMetrics(1) + 1
    ctypes.windll.user32.mouse_event(MOUSEEVENTF_MOVEABS, x, y, 0, 0)
    ctypes.windll.user32.mouse_event(MOUSEEVENTF_CLICK, 0, 0, 0, 0)