Inserite questo nel generale del form
Private Declare Function GetWindowLong Lib "user32" Alias "GetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As Long) As Long
Private Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long
Private Const GWL_EXSTYLE = (-20)
Private Const WS_EX_APPWINDOW = &H40000


Per rendere invisibile il form mettete questo dove volete
SetWindowLong Me.hWnd, GWL_EXSTYLE,(GetWindowLong(hWnd,GWL_EXSTYLE) And Not WS_Ex_APPWINDOW)


E per ri-renderlo visibile


SetWindowLong Me.hWnd, GWL_EXSTYLE,(GetWindowLong(hWnd,GWL_EXSTYLE) Or WS_Ex_APPWINDOW)