Without the Control Shift Enter requirement, you can also use:
=MAX(A1,1)*MAX(B1,1)*MAX(C1,1)
This assumes that all values will be integer greater than 1, ie not a decimal value between 0 and 1.
If decimal values are likely then this will cover that:
=IF(A1<>0,A1,1)*IF(B1<>0,B1,1)*IF(C1<>0,C1,1)
Rob Henson
Please note the accepted solution will only work where the cells are next to each other, ie A1, B1 and C1 or at least on the same row or column. It will still work with blank cells between eg A1 to E1 but B1 and D1 are blank.
However, for cells that are dispersed, eg A1, B3 and C5, it will need to be one of the other options.
What do you intend to do?
Regards