Kathipa to back away from the scanner press the key for "duck". You can check which key it is in the menu under controls. It's either number 1 or 2 on the number pad of keyboard.
Kathipa when you are in the game go to the controls menu and see what key is used for "duck". If it is the number 1 on the keyboard it is referring to the numberpad to the right of the keyboard NOT the numbers above the letter keys.
You can change/reassign whatever key is shown for "duck" in the control menu. Try changing the assigned key and see if that works. Hope this helps. Good Luck.