The user may disable touchPad because of inconvenience caused by its responsiveness or sometimes it can get disabled on laptops. To enable and disable Touch pad restarting your PC may help. In the case of laptops with Windows OS like XP and Vista, changes in the mouse settings tab can enable and disable the TouchPad. Some laptops come with keyboard short cuts for this function. To run TrackPad, one can also use the website called Synaptics that provides synaptic drives and software which is needed.
Sometimes the TouchPad can be disabled for no apparent reason on laptops. To reactivate it, first try restarting your PC. If that doesn't help try the following:
Go to Control Panel > Mouse > Settings
Click Enable (or Disable to disable)
On some models, there is a keyboard shortcut to activate or deactivate the touchpad. For example, on an ACER machine, press FN + F7
You can click "Reset device" if neither of those solutions work.
On the latest laptops, there is a special button to enable/disable the TouchPad.