Per dare la trasparenza alla form puoi usare la seguente funzione da inserire in un modulo bas:
codice:
Option Explicit

Private Const GWL_EXSTYLE = (-20)
Private Const LWA_ALPHA = &H2
Private Const WS_EX_LAYERED = &H80000

Private Declare Function SetLayeredWindowAttributes _
Lib "user32" _
(ByVal hwnd As Long, _
ByVal crKey As Long, _
ByVal bAlpha As Byte, _
ByVal dwFlags As Long) As Long

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
'------------------------------------------------------------------
Public Sub FormFade(ByRef frmForm As Form, ByVal Opacity As Long)
    Dim Msg As Long
    frmForm.Show vbModeless
    Msg = GetWindowLong(frmForm.hwnd, GWL_EXSTYLE)
    Msg = Msg Or WS_EX_LAYERED
    SetWindowLong frmForm.hwnd, GWL_EXSTYLE, Msg
    SetLayeredWindowAttributes frmForm.hwnd, 0, Opacity, LWA_ALPHA
    frmForm.Refresh
End Sub
Poi nel modulo della form la richiami così:
codice:
Option Explicit
Private Sub Form_Load()
    Dim t As Single
    
' Imposta BorderStyle=0
' Livello di trasparenza:
    t = 200     ' da 0 a 255
    FormFade Form1, t

End Sub