The touchpad worked correctly after the first reboot after installation, but then, without making any changes on system, restarting again, the touchpad was totally disabled.
I'm working on a laptop Compaq Presario CQ-40 324la.
I sometimes face similar problem. Generally running the Synaptiks application once or twice fixes my problem. You can open the dashboard by pressing the Super
key and then search for application and select it using arrow keys and run it by hitting enter.