Delete rows that do not contain an email address

This explains it

Public Sub Test()
    Dim eRange As Range
    Dim Bool As Boolean
    Dim NotFound As Boolean
    Dim i As Long
    Bool = True
    NotFound = False
    With Sheet1
        For i = 1 To .Rows.Count
            If InStr(1, .Cells(i, "A").Value, "@") > 2 Then
                If Bool = True Then
                    Bool = False
                    Set eRange = Rows(i)
                    NotFound = True
                Else
                    Set eRange = Union(eRange, Rows(i))
                    NotFound = True
                End If
            End If
        Next i
        If NotFound = True Then
            eRange.EntireRow.Delete
        Else
            MsgBox "No e-mail found."
        End If
    End With
End Sub