The following bit of code, which requires the win32api, simulates a mouse click using Python under the Windows OS.
import win32api, win32con
def click(x,y):
win32api.SetCursorPos((x,y))
win32api.mouse_event(win32con.MOUSEEVENTF_LEFTDOWN, x, y, 0, 0)
win32api.mouse_event(win32con.MOUSEEVENTF_LEFTUP, x, y, 0, 0)
click(100, 100) # simulate mouse click at 100px, 100px
