keyboard typing wrong letters

My keyboard is typing incorrect letters in some cases. Also the trackpad is not working. However in Windows 7 device manager, there are no errors being shown. I did open the laptop to change to a M.2 drive. I may have hit something by accident. Perhaps a ribbon or cable is out. I looked at the maintenance and service guide for answers. They suggest that a keyboard flex cable may have come loose or is not lined up properly. There is no good picture of this in the service guide. Can someone help me? Is there something else that could be wrong? I played with the shift, ctrl, alt, etc. keys and that made no difference.