I installed a program to my gertie and when my mac os x restarted the mouse is in the top left corner and neither my mouse or my keyboard work. Before I installed it everything had worked fine for several years
Turn off Your Mac and reset it while holding down the Shift button. This will boot you into "Safe Mode" which will boot just in basic mode and you can remove that program (and any Startup things it has in System Preferences->Accounts, Login Items tab) and then just reset using the Reset Your PRAM mode while restarting.