Can anyone please advise me how I would write a worksheet selection
event code so that when you select a particular worksheet it turns the
calculation on and then turns it off when you select another worksheet
in the same workbook.

I have one particular part of a worksheet that extracts a whole load
of information from the main sheet using a series of sumproduct
formulas but of course this is very slow in doing the calculations and
as this information is only required on the odd occasion it would be
beneficial and a whole lot quicker if I was able to turn off the
calculation on that particular worksheet until it was required.

Any help would be most appreciated. -

ps I have never used a worksheet event but have been advised that this
is the best course of action - I have no idea how or where to input
this coding/information

Thanks

Bjthebear