thanks for your reply. I can sort of understand where you are going with the macro run command and I think I can get a good start from there and figure things out.
To clarify my first question about the space key down, I'm trying to use this function in a game where I need to press the space key down for certain amount of time. For example, the longer I press the key down, the larger the power I charge for the missile. I agree with you that Windows interprets holding down space key as repeated keystrokes. I also thought it would work vice versa (even in the game) - i.e. fast repeated stroke of space key in the game would be equivalent as holding down the space key. However, I can't get it to work for some reason. It seems like the game doesn't recognize the repeated key stroke as holding down the space key. Unfortunately, I don't know how the game checks if I'm pressing the space key down or not. But, given this much explanation&your knowledge of computer programming, do you think there's a way to solve this problem?