I'm assuming from this that Fedora came with k3b. That being the case, installing k3b again is not likely to fix anything.
First, check to see that you are in the proper group. It's typically something like "cdrom" or "optical". You can see the choices in your GUI system admin menus, or you can do it in a terminal.
To see all groups: more /etc/group
To add yourself to--eg--optical:
su ##to become root
usermod -a -G optical <username>
Alternatively, just run k3b as root (from a terminal)
Beyond this, tell us what is not working.
If you DON'T have k3b, then surely Fedora has some other CD-burning application.