Installation problem with new nvidia driver (440.82) and old cuda (8.0 and 9.0)

In order to run a paralleling computing program (VMD) in ubuntu 16.04 LTS using an GTX-780Ti and GTX970, a nvidia driver (NVIDIA-Linux-x86_64-440.82.run) and cuda toolkit are like to be installed. The nvidia-smi command work fine immediately after 440.82 installation, but was failed and showed “NVIDIA-SMI has failed because it couldn’t communicate with the NVIDIA driver. Make sure that the latest NVIDIA driver is installed and running.” after installation of either cuda 8.0 (cuda_8.0.61.2_linux.run) or 9.0 (cuda_9.0.176_384.81_linux.run) without any error. Guidance and suggestions will be highly appreciated.