Validation & Formulas

[Jessard]

Hi again,

Is it possible to stop a cell being changed if it does not meet certain
criteria. Ie. if it is true or false or just some other text. For example,
if the text typed in is something other than true or false stop the cell from
being updated (or put it's original value back in).

Also, formula's do not seem to work when referring to values on a second
sheet. Is there a way around this? It will work onload but not whilst
changing cells manually.

Thanks,
Jesse