I think kies has an emergency fix feature or something (never used kies myself)
Assuming you're not interested in flashing custom roms / retaining warranty (research: knox) then download the latest offical rom and flash it through odin. Then boot to recovery, wipe data / factory reset and you'll be good to go. Obviously having lost all your data.
If you don't know how to do those things spend some hours researching them.
If you haven't read prepare to be ignored, or worse.