Hello Mohamed,
Please check under the device manager and see if the drivers are recognized. You can access the device manager by right click the Windows Icon and click device manager. If the drivers are not installed, please go the following link.
http://support.asus.com/download/options.aspx?SLanguage=en
In the link just download the touch pad drivers and install it.
Another solution can be to check if the touch pad is connected to the right socket by disassembling the laptop.