k95 rgb platinum The 4 key (not number pad4) wont work

i recently brought a k95 platinum, first one i had was the speed silver version, it was fine for a few days, but randomly the 4 key just stopped working, i took it into where i brought it and they 4 worked on there pc, i took it home it worked while logging into my computer then immediately stopped.

i then returned it for a different k95 plat, this time with the brown silvers and again on an entirely different keyboard and im having the same issues, ive tried updating the drivers and there all up to date and its really confusing me, any ideas ?

If CUE is installed, check and make sure a empty action is not assigned to it.

If not, check your background apps as they may have a hotkey action assigned to the key.