Change value based on another cell's value
 

I've got R1C1 and R1C2 which are both manually entered values. R1C3 is a formula that multiplies the two {=sum(r1c1*r1c2)}. R1C3 also has conditional formatting (if the value equals zero, then make the cell red and bold).

R20C3 has a formula to add the entire column {=sum(R1C3:R20C3)}.

What I want to do is force the vaule of R20C3 to zero (disreguarding the formula) if the value of R1C3 is zero. Any help would be appreciated.

Thanks.

Change value based on another cell's value
 

=IF(R1C3=0,0,SUM(R1C3:R20C3))

Also note that the use of sum for the product is redundant. A simple:

=r1c1*r1c2

would suffice.

HTH
Kostis Vezerides