private void Form1_SizeChanged(object sender, EventArgs e)
{
    if (this.WindowState == FormWindowState.Minimized)
    {
 
    }
}

Imports System
Imports System.Windows.Forms
 
Public Class Form1
 
    Private Const WM_SYSCOMMAND As Int32 = &H112
    Private Const SC_MINIMIZE As Int32 = &HF020
 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Me.TopMost = True
    End Sub
 
    Protected Overrides Sub WndProc(ByRef m As Message)
        If m.Msg = WM_SYSCOMMAND Then
            If m.WParam.ToInt32() = SC_MINIMIZE Then Exit Sub
        End If
        MyBase.WndProc(m)
    End Sub
 
    Private Sub Form1_LocationChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.LocationChanged
        If Me.WindowState = FormWindowState.Minimized Then
            Me.WindowState = FormWindowState.Normal
        End If
    End Sub
End Class