Since you've already tried pressing fn+F7 and it didn't work, please do try these other troubleshooting steps that may help. First, connect an external USB mouse for troubleshooting purposes.
- Go to Device Manager and uninstall the Touchpad driver.
- Once uninstalled, reboot your laptop and it should reinstall the driver automatically.
- If it doesn't reinstall, download and install the Touchpad driver from Acer's Support site.
- Once installed do test if your Touchpad will work or not.
- You last resort if all these will not work is to run a Factory Reset.
- If the Factory Reset will not solve the problem them it's the Touchpad itself that is faulty.