when i play Medal of Honor Allied Assault the mouse moves around the screen realy slow. when i use a serial mouse it works fine but now i have an optical mouse.

First check the mouse settings in control panel. Tracking speed etc...

Then, of course, look through the settings of the game itself, for any mouse settings. But I know nothing of that game, haven't played it.

But all I can is maybe with the new fangled mouse, there is some controlling software that is setting a "profile" for a game, like what joystick software does. But if there is something like that, you'll see it in control panel.

Other than that, I can't really say what it might be!