You can just uninstall Easy CD Creator 4 if you don't want to use it anymore and then install Nero. No special precautions are necessary, and a change doesn't cause problems. If you want to be extra cautious about removing all traces of Easy CD Creator, you can follow the instructions at The correct method of uninstalling and reinstalling Easy CD Creator 4.X
and stop at step 8.
You can also leave Easy CD Creator 4 installed and install Nero. They should work together without any problems as long as you install only one packet writing program, either DirectCD or InCD (but not both).
Reports of incompatibilities can usually be traced to the installation of more than one packet writing program.