Compile error: Method or data member not found.

Trying to run the code below on a sheet but keep getting compile error. In bold is what is erroring (is that a real word?)

My aim is to have it so a box (5,2) has either a Y or N entry.
If it is Y then (9,8) = (10,31) on this page.....this works
Also if Y then another cell (9,3) = value in (1,1) from another page in this workbook (Main Data)

Where have I gone wrong??

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
If Cells(5, 2) = "N" Then
Cells(9, 8) = "0"
ElseIf Cells(5, 2) = "Y" Then
Cells(9, 8) = Cells(10, 31)
ElseIf Cells(5, 2) = "Y" Then
Worksheet("GPS Mapping").Cells(9, 3).Value = ThisWorkbook.Worksheet("Main Data").Cells(1, 1).Value



End If
End

End Sub

Should be "Worksheets" and not "Worksheet".

omg....can't see the wood for the trees

Thanks

So now I have got past that little oversight the new code no longer gives compile errors.....but it does not return the number from Main Data cell (7,6), have I missed something else?

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
If Cells(5, 2) = "N" Then
Cells(9, 8) = "0"
If Cells(5, 2) = "Y" Then
Cells(9, 3) = Worksheets("Main Data").Cells(7, 6).Value
ElseIf Cells(5, 2) = "Y" Then
Cells(9, 8) = Cells(10, 31)
End If
End If
End Sub

Try this.

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
If Cells(5, 2).Value = "N" Then
    Cells(9, 8).Value = "0"
    If Cells(5, 2).Value = "Y" Then
        Cells(9, 3).Value = Worksheets("Main Data").Cells(7, 6).Value
    ElseIf Cells(5, 2).Value = "Y" Then
        Cells(9, 8).Value = Cells(10, 31).Value
    End If
End If
End Sub

Both your conditions are the same

If Cells(5, 2).Value = "Y" Then
...
ElseIf Cells(5, 2).Value = "Y" Then

I understand that both of the conditions are the same, have just added that extra elseIf and is OK now, thanks Stephen and Stepsahead