Hi,
I have been using MS Excel for years and using various formulae in
my spreadsheets without any problems

Now I have just noticed that this formula, for example: =SUM(F100:G99)
cannot be calculated.Excel reports that Cell references in the formula
refer to the formulas result, creating a circular reference. How can
that be?
Also neither SUM(F100+G99) and (F100+G99) work.
Further I have noticed that ALL of my previously working formulae for
various cells have changed;or rather the results have changed.
For example, this formula: =SUM(B103+C102) is now #VALUE!
Where B103 = 83 and C102 = 41.
I have checked formatting of cells, but nothing I do solves the problem.

Thanks
--
Bob H
Leeds UK