Hmmm seems like there is likely a blocking package here. You would need to remove that one first.
You can easily find out the names of the packages by trying to install via console.
I am guessing you were trying to install the 450xx prime driver, so this would be the command for that:
mhwd -i pci video-hybrid-intel-nvidia-450xx-prime
If you are still unsure after reading the tutorial, please post the output you get back from the command.