This is how I would probably do it:

Sub DeleteNonContinousRows()

'Place the cursor at the correct cell in the sheet
Range("A1").Select
Application.Goto Reference:="R2C1"

For Counter = 1 To 400 '2000/5
ActiveCell.Range("A1:A4").Select
Selection.EntireRow.Delete
ActiveCell.Offset(1, 0).Range("A1").Select
Next Counter

End Sub