I want to send some key strokes to another application. I tried:

Keybd_event and sendinput

However, it seems the application does not get the key strokes, since after keybd_event or sendinput, the application does not act as it is supposed to be (i.e. if send a 'ESC', it should pop up a window). The weird thing is if I press the 'ESC' directly, the window pops up. And, if I use my program on 'Notebook', it is ok (i.e. if I send 'a', 'a' will show in notebook the same as I press 'a' directly).

What's the possible reason? Is it possible for me to overcome this?

BTW, the application I'm working on is a video game.

thanks