Hi, I uninstalled the driver and then reinstalled it using the following commands:
sudo pacman -Rdd linux54-nvidia-455xx nvidia-455xx-utils
sudo pacman -S linux54-nvidia nvidia-utils
Everything worked too. 
But now there is a warning message in Manjaro-Settings-Manager about MHWDCONFIG. I initiated this as a test and that’s when I noticed it.
Do i have to change it for future updates? And if so, how? Or can i ignore the message?
That’s under “show details”:
Starting
Warning: config ‘/var/lib/mhwd/local/pci/video-nvidia-455xx/MHWDCONFIG’ is invalid!
Skipping already installed config ‘video-nvidia’ for device: 0000:01:00.0 (0300:10de:13c2) Display controller nVidia Corporation GM204 [GeForce GTX 970]