Please do try these troubleshooting steps that may help.
- Start by pressing fn+F9 at the same time.
- If that will not work, uninstall/reinstall the Touchpad driver.
- Go to Device Manager and uninstall the Touchpad driver.
- Reboot the laptop once uninstalled and it should reinstall the driver automatically.
- After the reboot do test the Touchpad again and see if it will work or not.
- Next to try if all these will not work is to run System Restore. Restore the laptop into an earlier date or time when the touchpad was working.
- Here's how to run System Restore: http/windows.microsoft.com/en-PH/windows-8/restore-refresh-reset-pc