Genius external keyboard working improperly on Macbook Pro
The behavior sounds like a Num Lock or Fn key is stuck on. Does the keyboard behave this way on a PC without the Genius keyboard driver installed?

I don't know how much effort you want to put into this, but Karabiner is a general-purpose tool for remapping just about anything about a keyboard attached to a Mac. You can make rules which only affect a single device. How much do you like this keyboard?