Find zero value and use value from cell above as formula

[sickolas]

Hi Guys/Girls

Im a virgin to this forum, I hope someone can help.

I am trying to construct a formula for my boss to indentify month % change against base year.

For example, if cell C7 jul-11 is zero, then the formula should take C6 (jun-11) and sum C6-B6(jun-10) /abs(B6)..

I am not sure if I sould be using an IF formula or Vlookup or even use VBA.

Any help would be appreciated.

Regards

Sickolas