Explain that the (wireless/optical) mouse or touchpad might need to be woken up (e.g. by clicking a button or wiggling the mouse for a while) before they will work.
Wireless and optical mice, as well as touchpads no laptops may need to "wake up" before they will work. To wake up your mouse or touchpad you can click on a mouse button or wiggle the mouse.
Laptop touchpads sometimes have a delay after you stop typing before they will start working. This is to prevent you from accidently touching the touchpad with your palm while typing.