#### Logic Problem

Hi everyone, i posted my problem earlier but there was no reply, so i hope this time some great programming angels can come and help me out. I know there is something wrong with the logic of syntax that im using here but i just cant figure out how to fix it...i just want a message box to pop put once it has checked all the rows and columns in excel file and is not able to find the data....so the message box will appear as "Invalid data"....Please help and thanx a lot...

b=1
c=1
For a = 9 To 20

If LCase(Sheet3.Cells(a, 4)) = moo Then

Sheet5.Cells(b + 7, 1) = Sheet3.Cells(a, 2)
Sheet5.Cells(b + 7, 2) = Sheet3.Cells(a, 3)
Sheet5.Cells(b + 7, 3) = Sheet3.Cells(a, 10)
Sheet5.Cells(b + 7, 4) = Sheet3.Cells(a, 14)
Sheet5.Cells(b + 7, 5) = Sheet3.Cells(a, 24)
Sheet5.Cells(b + 7, 6) = Sheet3.Cells(a, 5)
b = b + 1

ElseIf LCase(Sheet2.Cells(a, 4)) = moo Then

Sheet5.Cells(c + 7, 1) = Sheet2.Cells(a, 2)
Sheet5.Cells(c + 7, 2) = Sheet2.Cells(a, 5)
Sheet5.Cells(c + 7, 3) = Sheet2.Cells(a, 9)
Sheet5.Cells(c + 7, 4) = Sheet2.Cells(a, 18)
Sheet5.Cells(c + 7, 5) = Sheet2.Cells(a, 25)
Sheet5.Cells(c + 7, 6) = Sheet2.Cells(a, 6)
c = c + 1

Else
'MsgBox "Invalid"
End If
Next a
End Sub