N360_BACKUP folder at 702GB! "Delete backup files" option "greyed out"-cannot access it?!

So I am trying to "manage" this nightmare created by my norton security suite, aka N360 posseessed by comcast version.

I want to delete the backup files I DO NOT need, and keep the ones that are essential. BUTTT, when I try to do this in the norton manage backup area, the option to "delete backup files" is greyed out, I cannot click on it, it doesnt do anything, its unaccessable, etc . I do not think it is wise to delete the entire folder in my "C" drive, because ONE: there are definitely important back up files possibly in there-lol, and TWO: I have seen and experienced after deleting such a folder/file, it disapperars, YET, still hoigs up all the memory and now you cannot find NOR access the folder/files any longer.