....
 
Protected StartLocation As Point
    Protected StartDragLocation As Point
.....
 
    Private sub form1_MouseMove(.......) Handles MyBase.MouseMove
        If e.Button = MouseButtons.Left Then
            Dim p As New Point(e.X, e.Y)
            p = me.PointToScreen(p)
            Me.Location = New Point(StartLocation.X + p.X - _
              StartDragLocation.X, StartLocation.Y + p.Y - StartDragLocation.Y)
        End If
    End Sub
 
    Private Sub form1_MouseDown(.....) Handles MyBase.MouseDown
        If e.Button = MouseButtons.Left Then
            StartLocation = Me.Location
            StartDragLocation = Me.PointToScreen(New Point(e.X, e.Y))
        End If
    End Sub
 
.....