somthing like this will loop through a range, then stop and perform a
calculation when a non-blank cell is encountered.

Sub findFirstNonBlankCell()

Dim myRange As Range
Dim myVar As Range
Set myRange = Range("A2:A10") 'set range

'begin loop
For Each myVar In myRange
Set nextVar = myVar.Offset(1, 0)

If myVar = "" Then 'test to see if cell is
empty
Set myVar = nextVar 'proceed to next cell if empty
Else 'else perform a
calc.
myVar.Value = myVar * 2 'peform a calucation
End If
Next
End Sub