There might be something in your Mouse control panel that controls the touchpad. Look on all the tabs--there might be a drop down list of devices that you can use to get to the settings for the touchpad. Look for a checkbox that enables/disables the touchpad.
In your program menu, look for a program with the name of the touchpad. The driver installer program could have installed a separate touchpad control program. Also, check out all the icons down by your clock.
In your Device Manager, under Mice..., is your touchpad device listed? Is there a ?, X, ! next to it?