Did you try typing the phrase "1904 date system" into Excel help?
--
David Biddulph

"Adnan" (donotspam) wrote in message
...
Thanks for your response Ron, how do I implement that?

Also, I've seen something close to what I need with Dadeif function but
cannot implement.

"Ron Rosenfeld" wrote:

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

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