VBA Script working and now is not - excel

Question

I wrote a very quick script for VBA that takes a spread sheet and organizes it appropriately. For some reason I have just tried using it and I get a user defined error at this loop:
Dim qu As Long
For j = i To 10 Step -1
If Cells(j, 10) = "" Then
qu = j - 1
Do While Cells(qu, 10) = Cells(qu - 1, 10)
Cells(qu, 11) = 10
Cells(qu - 1, 11) = 10
qu = qu - 1
Loop
Cells(j - 1, 11) = 10
End If
Next j
The whole code looks like this:
Sub PopulateNF()
i = 10
Do While Cells(i, 2) <> ""
i = i + 1
Loop
For k = 10 To i Step 1
If Cells(k, 1) <> "" Then
Cells(k, 10) = ""
Else
If InStr(1, Cells(k, 2), "Received") Then
Cells(k, 10) = -1
ElseIf InStr(1, Cells(k, 2), "Workflow") Then
Cells(k, 10) = 0
ElseIf InStr(1, Cells(k, 2), "Forwarded") Then
Cells(k, 10) = 1
ElseIf InStr(1, Cells(k, 2), "Review Response") Then
Cells(k, 10) = 2
ElseIf InStr(1, Cells(k, 2), "Responded and Closed") Then
Cells(k, 10) = 4
ElseIf InStr(1, Cells(k, 2), "Sent") Then
Cells(k, 10) = 3
ElseIf InStr(1, Cells(k, 2), "Sent and Closed") Then
Cells(k, 10) = 3
End If
End If
Next k
Dim qu As Long
For j = i To 10 Step -1
If Cells(j, 10) = "" Then
qu = j - 1
Do While Cells(qu, 10) = Cells(qu - 1, 10)
Cells(qu, 11) = 10
Cells(qu - 1, 11) = 10
qu = qu - 1
Loop
Cells(j - 1, 11) = 10
End If
Next j
For a = i To 10 Step -1
If Cells(a, 1) <> "" Then
Cells(a, 11) = 10
End If
Next a
Const colA As Long = 11
Dim lngRow As Long
Dim lngLastRow As Long
lngLastRow = Cells.SpecialCells(xlCellTypeLastCell).Row
lngRow = 10
Do While lngRow <= lngLastRow
If Cells(lngRow, colA) = "" Then
Cells(lngRow, 1).EntireRow.Delete
lngLastRow = lngLastRow - 1
Else: lngRow = lngRow + 1
End If
Loop
d = 10
Do While Cells(d, 2) <> ""
d = d + 1
Loop
For k = 6 To d Step 1
If Cells(k, 1) = "" Then
Cells(k, 1) = Cells(k, 6)
Cells(k, 6) = ""
Cells(k, 2) = Cells(k, 7)
Cells(k, 7) = ""
Cells(k, 3) = Cells(k - 1, 3)
Cells(k, 4) = Cells(k - 1, 4)
Cells(k, 5) = Cells(k - 1, 5)
Cells(k, 6) = Cells(k - 1, 6)
Cells(k, 7) = Cells(k - 1, 7)
Cells(k, 8) = Cells(k - 1, 8)
Cells(k, 9) = Cells(k - 1, 9)
End If
Next k
Const colAN As Long = 1
Dim lngRowN As Long
Dim lngLastRowN As Long
lngLastRowN = Cells.SpecialCells(xlCellTypeLastCell).Row
lngRowN = 9
Do While lngRowN <= lngLastRowN
If Cells(lngRowN, colAN) = "" Then
Cells(lngRowN, 1).EntireRow.Delete
lngLastRowN = lngLastRowN - 1
ElseIf InStr(1, Cells(lngRowN, colAN), "_") Then
Cells(lngRowN, 1).EntireRow.Delete
lngLastRowN = lngLastRowN - 1
Else: lngRowN = lngRowN + 1
End If
Loop
Range("a9").CurrentRegion.Sort key1:=Range("a9"), order1:=xlAscending, Header:=xlGuess
Range("D:D").NumberFormat = "mm/dd/yyyy"
Range("F:I").NumberFormat = "mm/dd/yyyy"
Range("C:I").HorizontalAlignment = xlCenter
Range("a:a").VerticalAlignment = xlTop
Range("J:K").EntireColumn.Delete
Range("A:J").Font.Color = vbBlack
MsgBox ("Reformatting Complete")
End Sub
Any help would be greatly appreciated!

Answer 1

Stepping through the code looks like your loop doesn't know where to end.
Basically the line:
Do While Cells(qu, 10) = Cells(qu - 1, 10)
is never false and "qu-1" eventually becomes negative.
I'm not sure if this works with the greater bulk of your code, but you could try:
Do While qu <> 1
That should close your loop while still allowing you to modify cell values within the loop.