|Try restarting your computer, even if you have to use the power button and hold it down until it shuts down and then restart it.|
Try an external USB mouse and see if that works and report this back (this can tell us some things).
Update your motherboard and touch pad drivers from the mfg's website. If this alone does not help, then go to Control Panel>Device Manager and delete your touch pad and then detect hardware or restart and this should fix it with the new driver you just installed.
Try a system restore back to when it all worked.
You have to be a little bit crazy to keep you from going insane.