Efficient Loops in VBA - arrays

Question

I have written a VBA Macro which works, but takes too long because the database is also very big.
I know this can be optimized via Arrays, but I am not sure how to make it.
Could someone help me please?
'Identify how many rows are in the file
finalrow = ActiveSheet.Cells(Rows.Count, 6).End(xlUp).Row
'fill the empty fields which requires the part number and description
For i = 2 To finalrow
If Cells(i, 3) = 0 Or Cells(i, 3) = "------------" Or Cells(i, 3) = "e" Or Cells(i, 3) = "111)" Or Cells(i, 3) = "ion" Then
If Cells(i, 4) = 0 Or Cells(i, 4) = "-----------" Or Cells(i, 4) = "Location" Then
Range("A" & i & ":H" & i).Select
Selection.Delete Shift:=xlUp
i = i - 1
Else
For j = 1 To 3
Cells(i, j) = Cells(i - 1, j)
Next
End If
End If
If Cells(i, 1) = 0 Then
Cells(i, 1) = Cells(i - 1, 1)
End If
If Cells(i, 4) = 0 Then
Range("A" & i & ":H" & i).Select
Selection.Delete Shift:=xlUp
i = i - 1
End If
Count = Count + 1
If Count = finalrow Then
i = finalrow
End If
Next

Answer 1

I combined your code with my answer to excel Delete rows from table Macro based on criteria, that I just finished posting. It is super fast. Please check out my other answer for details.
You may need to adjust the Target range. If your data starts in A1 and does not have any completely blank rows than it should work.
Sub DeleteRows()
Dim Start: Start = Timer
Application.ScreenUpdating = False
Application.Calculation = xlCalculationManual
Const PreserveFormulas As Boolean = True
Dim Target As Range
Dim DeleteRow As Boolean
Dim Data, Formulas, NewData
Dim pos As Long, x As Long, y As Long
Set Target = Range("A1").CurrentRegion
Data = Target.Value
If PreserveFormulas Then Formulas = Target.Formula
ReDim NewData(1 To UBound(Data, 1), 1 To UBound(Data, 2))
For x = 2 To UBound(Data, 1)
DeleteRow = True
If Data(x, 3) = 0 Or Data(x, 3) = "------------" Or Data(x, 3) = "e" Or Data(x, 3) = "111)" Or Data(x, 3) = "ion" Then
If Data(x, 4) = 0 Or Data(x, 4) = "-----------" Or Data(x, 4) = "Location" Then
DeleteRow = False
End If
End If
If Data(x, 4) = 0 Or Data(x, 4) = "-----------" Or Data(x, 4) = "Location" Then DeleteRow = False
If Not DeleteRow Then
pos = pos + 1
For y = 1 To UBound(Data, 2)
If PreserveFormulas Then
NewData(pos, y) = Formulas(x, y)
Else
NewData(pos, y) = Data(x, y)
End If
Next
End If
Next
Target.Formula = NewData
Application.Calculation = xlCalculationAutomatic
Application.ScreenUpdating = True
Debug.Print "Execution Time: "; Timer - Start; " Second(s)"
End Sub

Answer 2

I'd start simply with this:
'Identify how many rows are in the file
finalrow = ActiveSheet.Cells(Rows.Count, 6).End(xlUp).Row
'fill the empty fields which requires the part number and description
For i = 2 To finalrow
Set ci3 = Cells(i, 3)
If ci3 = 0 Or ci3 = "------------" Or ci3 = "e" Or ci3 = "111)" Or ci3 = "ion" Then
Set ci4 = Cells(i, 4)
If ci4 = 0 Or ci4 = "-----------" Or ci4 = "Location" Then
Range("A" & i & ":H" & i).Select
Selection.Delete Shift:=xlUp
i = i - 1
Else
For j = 1 To 3
Cells(i, j) = Cells(i - 1, j)
Next
End If
End If
If Cells(i, 1) = 0 Then
Cells(i, 1) = Cells(i - 1, 1)
End If
If Cells(i, 4) = 0 Then
Range("A" & i & ":H" & i).Select
Selection.Delete Shift:=xlUp
i = i - 1
End If
Count = Count + 1
If Count = finalrow Then
i = finalrow
End If
Next