Excel question

Welp, I can't figger it out. I'm bafoodled again.
Can someone tell me how to change the way a date is displayed in Microsoft Excel?

In the first column of my chart it shows the date as (i.e.) 3/6/2004
(that's how I want it to look.)

In another column further over where I enter a later day, no matter how I type it in it always changes and shows as 6-Mar
(which is how I don't like it!)

I've also noticed that if I put in a note before that date then it will show the date as 3/6 , for example " 2 each 3/6".

Is there some way to just make the date in this form "3/6/2004" for that particular column? How come it does in the first column but not in the other one?