General formatted to Date Format

I'm working in Excel 2003 and when I open a new sheet it is set to general but if I type a date in a cell it is automatically formatted to date. By it being formatted to date it removes the zero from the date 09/16/2010 and makes it 9/16/2010.

My macro is using the date as a matching criteria but when it is ran on a co-workers desktop it does not work because their machine keeps the date as general (09/16/2010). When building the macro on my desktop it was alway formatted to date so the macro worked.

I'm figuring my desktop has some type of auto filter set to automatically format a cell to Date when a date is entered.

Is this possible if so how can I turn it off?