On Thu, 6 Mar 2008 21:05:00 -0800, Adnan (donotspam)
wrote:

I have a start date in A1 formatted as dd/mm/yyyy hh:mm
I have another date (finish date) in cell B1 formatted the same (dd/mm/yyyy
hh:mm).
I have a formula in C1 that subtract A1-B1, cell is formatted as dd:hh:mm
It works if results are positive, if negative I get an error, lots of pond
signs within the cell (#########)

Any tip/help is much appreciated.
Adnan

Unless you switch to the 1904 date system, you will not be able to display
negative date/times using date formatting
--ron