OK here is my currently installed driver:
The tool GPU-Z is quite handy because you can also monitor the sensors and write a log file, you can download it for free following this link:
http://www.gpu-z.de/
Maybe you didnīt uninstall the new driver properly, before applying the old one?
Another reason could be is that the new nvidia 2xx chip generation was introduced with the 178.xx driver suite and causes some side effects with older GPUs.
br
Michael