Knowing whether you are using a Mac or a PC would be rather important to answer your question.
Anyhow, there is not need to delete any program folder manually. Simply use the respective method of your OS.
LR CC created a copy of your LR5 catalog and upgraded it. If you remove LR5 you might want to remove the catalog file as well as the preview folder (make sure not to delete the new ones of LR CC ).
Here is how to find everything: https://helpx.adobe.com/lightroom/kb/preference-file-locations-lightroom-41.html