when i change data in a sum forumla, the sum doesn't change?

[richard_kta]

i am doing a simple sum formula, using it several times in the worksheet, and
it used to work fine, however, suddenly now the formulas are only working
after the initial calculation, if i go back and change data later on, the
formula doesn't reflect any changes and special pasting of the formula only
reproduces the value of the original calculation! I want the Sum function to
work as it should. Reflect changes as they are made and be able to paste a
function to another group of cells!

[bill k]

does the formula recalculate when you press F9

have a look at <tools><options><calculation>
is it on manual?

This may have been caused by a previous book opened and saved with the setting on manual.