Stopping a Loop in a macro when a keyword appears.

Hi guys

I have this bit of code on the end of a macro, to calculate a value and move on to the next line. When Cells(i, 1).Value have "(blank)" written in the cell, I want to stop the loop, how do I do that?

For i = 5 To NoRows
Cells(i, 8).Value = Cells(i, 2).Value * Cells(i, 4).Value * Cells(i, 6).Value / Cells(i, 3).Value
Next i
End Sub

Don't think having the workbook is essential to solving this, but if it's required i'll upload it