Multi-Calendar Problem

For some reason either my Microsoft Outlook or my iPhone 5 decided to create a new calendar which it now syncs to rather than the one I keep. Every entry I make on either my computer or my iphone I have to change to the color-coded calendar I use. The other one is not color-coded. I'm afraid to delete the calendar I don't want fearing it will delete all my entries. How do I point the sync to the correct calendar? When I try to mark just one in iTunes it automatically rechecks the other one as well. Any help would be appreciated.