Try pressing combination such as Function key + F3 or Function key + F5 or Function key + F9 or Function key + F11.Try pressing fn and F1 together, then fn and F2 together and so on and check that your problem has been solved or not.Try Pressing F1, F2, F3 and so on individually and keep checking your problem get fixed or not.If you are using Acer Laptop, you can enable or disable touchpad using F7 in acer laptop keyboard.
