It's possible that your calc is not producing absolute zero (something like 0.0000001). You can see this by increasing the decimal spaces. Other than this, Accounting format should give you the results that you desire.
Have you tried :
view
toolbars
customise
commands
catagories = format
commands = , comma style
click on ", comma style" and drag it into an appropriate place in your toolbar
close
you should now have a "," button in your toolbar
highlight your range of data and click on the new "," button : this will comma format your numbers but will also show any zeros as a mere "-"
As Scott rightly points out though, sometimes a 0.00 is really a 0.00000000000037864 etc etc so it will not recognise this as zero.
HTH
Chris
Sandy
Try pasting the following in the custom category
_($* #,##0.00_);_($* (#,##0.00);_($* "-"??_);_(@_)
Choose the cell,
Choose Format
Choose Number
Choose Custom
On the right where it says Type paste the above in the open box below.
See if this does the trick and let me know..
Brian