Unable to calculate business days and hours (Excel Noob).

My team uses a SharePoint Calendar, in which they enter their time off request. Usually they request just a couple of hours and request the whole day, SharePoint uses 24 hrs when requesting a full day off.
This is how the data looks:
A2 contains start time: 2/15/2012 0:00
B2 contains end time: 2/15/2012 23:59

I've used the formula found on this thread and it does give me the 23:59 hours requested:
http://www.excelforum.com/excel-form...me-stamps.html

However, when the time off request is for more than 1 day, it still , the result still is 23:59 instead of multiplying it by the amount of days requested and it seems to not work properly when applying it to the other cells in the column.

I have also tried using the formula on this thread to calculate business hours, replaced the formula values to match my worksheet and it did not work properly:

http://www.excelforum.com/excel-form...ess-hours.html

I have attached a worksheet with the "issues" I'm facing. If anyone has an idea or could open my eyes and make me see something that I'm missing, I would really really appreciate it.

Thanks dogberry! Making this change actually gives me values on the column, however, it is giving me a total of 21:00 hrs when a full week is requested for time off:

6/18/2012 0:00 6/22/2012 23:59

This particular time frame goes from Monday to Friday and the formula gives me a total of 21 hrs. If I'm not mistaken, 5 days x 9 workings hours should total 45 business hours requested. If I'm mistaken please let me know.