Hi! Experts

In column A i have Dates with different Format.

Like

Dates
28/08/09
05-09-2009
8.27.2009
8.27.2009
8.27.2009
8.29.2009
25/08/09
25th Aug
31.08.09
2nd sep
2nd sep
4th Sep


Now i want to Change this Dates of MM-DD-YYYY FORMAT.

When i change the Whole Columnn i.e. Column A into mm--MM-DD-YYYY FORMAT.
Some Cell Apply this format some not.

Is it Possible to Change the Whole Column in a Once.

Or I have to go Manually. Column A has 1500 data.

Thanks in Advance

Hardeep kanwar