VBA Code Error "Invalid or unqualified reference" - excel

Question

I am very new to vba coding .
In the worksheet I am trying to add an additional column using macros-column (Q)by checking conditions in simultaneous columns J,K,O).So if certain conditions pass in each of the columns I want a value to be entered in Q column for the respective row. This is the piece of code I put together .
Option Explicit
Sub Button2_Click()
Sheet1.Activate
Dim i As Long
For i = 2 To .Cells(.Rows.Count, "B").End(xlUp).Row
'Check so that we only process non-empty cells
'(just in case there is an empty cell part-way through the data)
If Cells(i, 10).Value = "No" And Cells(i, 15) <= 0 Then
Cells(i, 17) = "Pending with employee"
Else
If Cells(i, 10).Value = "No" And Cells(i, 15) >= 0 And Cells(i, 11) = "No Action Pending" Then
Cells(i, 17) = "Pending with employee"
Else
If Cells(i, 10).Value = "No" And Cells(i, 15) >= 0 And Cells(i, 11) = "Pending With Manager" Then
Cells(i, 17) = "Pending with Manager"
Else
If Cells(i, 10).Value = "Yes" And Cells(i, 15) >= 0 And Cells(i, 11) = "No Action Pending" Then
Cells(i, 17) = "All Done"
'If Not IsEmpty(.Cells(i, "B").Value) Then
' If .Cells(i, "E").Value = "NA" Then'
'ThisWorkbook.Worksheets("CTCto TCC Conversion").Cells(i, "F").Value = "NA" '
End If
End If
End If
End If
Next i
End With
MsgBox "Column Created"
End Sub
It throws me an error Invalid or unqualified reference .Please help me if there any errors that need to be rectified for the code to run .
Thanks

Answer 1

Using the With Statement
BigBen has already answered your question. Here's an example with a little extra.
Check the two lines containing .Cells(i, 15).Value. One of them should probably have the equal sign removed.
If you write several conditions in one line of code, all of them will be evaluated even if the first one is already True (or False) making it less efficient than writing each condition in a new line. In practice, you most often won't feel a difference. I cannot decide which one is more readable or maintainable for you though.
Option Explicit
Sub Button2_Click()
With Sheet1
Dim i As Long
For i = 2 To .Cells(.Rows.Count, "B").End(xlUp).Row
If .Cells(i, 10).Value = "No" Then
If .Cells(i, 15).Value <= 0 Then
.Cells(i, 17).Value = "Pending with employee"
Else
If .Cells(i, 11).Value = "No Action Pending" Then
.Cells(i, 17).Value = "Pending with employee"
ElseIf .Cells(i, 11).Value = "Pending With Manager" Then
.Cells(i, 17).Value = "Pending with Manager"
End If
End If
ElseIf .Cells(i, 10).Value = "Yes" Then
If .Cells(i, 15).Value >= 0 Then
If .Cells(i, 11).Value = "No Action Pending" Then
.Cells(i, 17).Value = "All Done"
End If
End If
End If
Next i
End With
MsgBox "Column Created"
End Sub