Entering a new event problem on MacBook Pro

tI have used my MacBook Pro for 4 years. The problem is in iCal and only lately have I noticed it. When I add details , times, dates under a new event, after all details are in and I press the key to enter it into the calendar, it shows briefly and then reverts to saying it's a new event with none of the details I had entered. I have to remember to watch the calendar or I move on and then see something later that says New Event in my calendar with no details in it and have no idea what it represents. Help please