Disable / Enable the TouchPad
On laptops, sometimes your TouchPad is disabled for no apparent reason. To reactivate it, first try restarting your PC. If there’s no good change just try:
We need the software driver and your mouse are installed
This trick works in Windows XP and Vista
Go to Control Panel> Mouse> Settings tab of the device
Click <Enable> (or <Disable> to disable)
Notes:
On some models, there is a keyboard shortcut to activate or deactivate the touchpad. For example, a ACER, just do Fn + F7.
You can click Reset device if neither of those solutions will work.
The official website provides synaptics drivers and software needed to run your TouchPad.
Link:
http://www.synaptics.com/