I have a dell latitude e6400 with a backlit keyboard, the license wasnt on the laptop and the hard drive was destroyed so i put a new one and loaded ubuntu, However now the backlit keyboard won't work and i dont know of any programs that will fix the problem that work for linux, let me know if anyone has a solution. Please and thank you!
What version of windows did it have? If it was 7 and you upgraded to 10 no need. Also ALL Dell PC's, when using a Dell OEM disk, which can be found on the dell support site when you search for your PC, will auto activate. No need to a CD key on the laptop. If you can't find it, and it came with windows 7 let me know. All i really ever do is work with dell so I have ALL of the Dell OEM install disk from Window XP to Windows 10 (Even though on 10 you don't need them you can just use the Media Creation Tool and make a Bootable USB drive and it install no issue if you had windows 10 before)
Now with the back light, it could be that it needs the Dell Quick-set software. This is usually needed for the "Extra" stuff on a keyboard to work, but as far as I know not for the back light.
Hold the FN key and then press this key. that is a on/off switch for the Back light. You might have accidentally hit it (I did the same thing long ago and though the back light was just dead until i accidentally turned it back on and was like OHHHHH!