Excel 2007 : Dates in 2007

I am having trouble entering dates in 2007. Under 2003, I only had to type in the day and the month, hit the enter key, and the date would complete itself with the year. In other words, for today's date, I would enter '20/12', press enter, and the date would come up as '20/12/09' or '20 December 2009' automatically, depending on how I had it formatted. This does not happen in 2007. All I get in the cell is exactly what I enter. Can 2007 auto-complete dates like 2003 could?

I checked all the above, and they were already set as you suggested. The only way I have discovered in getting Excel to recognise my input as a date is to set my own custom format. However, sometimes Excel wants to change the day and month around like American format - how do I stop this?

I also notice when I go to the date formats that the location is set to Dutch (Belgium). How can I set the default to English (New Zealand)? I don't want to be changing this every time.....

Thank you soooo much! Problem solved, along with a few others! This is also a new computer, and I had completely forgotten about those settings! LOL!