Generate date stamp when data entered - excel

Question

I am trying to create a nonvolatile date stamp in Column A cells as entries are made in B, C and D cells in the same row.
Private Sub Worksheet_Change(ByVal Target As Range)
Dim i As Integer
For i = 2 To 10000
If Cells(i, “B”).Value <> “” And _
Cells(i, “C”).Value <> “” And _
Cells(i, “D”).Value <> “” And _
Cells(i, “A”).Value = “” Then
Cells(i, "A").Value = Date & " " & Time
Cells(i, "A").NumberFormat = "m/d/yyyy h:mm AM/PM"
End If
Next
Range("A:A").EntireColumn.AutoFit
End Sub
I made it go to 10000 for the simple fact I do not know how to tell it to go as long as entries are entered.

Answer 1

It appears that you want to receive a datestamp once columns B:D are filled and column A is still empty.
If you write values back to the worksheet, disable event handling and provide error control.
Option Explicit
Private Sub Worksheet_Change(ByVal Target As Range)
If Not Intersect(Range("B:D"), Target) Is Nothing Then
On Error GoTo exit_handler
Application.EnableEvents = False
Dim r As Range
For Each r In Intersect(Range("B:D"), Target).Rows
If Cells(r.Row, "B").Value <> vbNullString And Cells(r.Row, "C").Value <> vbNullString And _
Cells(r.Row, "D").Value <> vbNullString And Cells(r.Row, "A").Value = vbNullString Then
Cells(i, "A").Value = Now
Cells(i, "A").NumberFormat = "mm/dd/yyyy h:mm AM/PM"
End If
Next t
End If
exit_handler:
Application.EnableEvents = True
End Sub

Answer 2

Try this to get rid of the loop:
Private Sub Worksheet_Change(ByVal Target As Range)
Dim i As Integer
If Target.Count = 1 And Target.Column > 1 And Target.Column < 5 Then
If Cells(Target.Row, "B").Value <> "" And Cells(Target.Row, "C").Value <> "" And Cells(Target.Row, "D").Value <> "" And Cells(Target.Row, "A").Value = "" Then
Cells(Target.Row, 1).Value = Now
Cells(Target.Row, 1).NumberFormat = "m/d/yyyy h:mm AM/PM"
Range("A:A").EntireColumn.AutoFit
End If
End If
End Sub
In short, when you make a change on column B C or D, it will check if All 3 for that Row are filled and then put the time stamp if it doesnt have one. Skipping the loop. If you are pasting data instead of typing it, it will not work, instead use the loop from Pawel's answer.