Without code we can't see what might be wrong..
But this is what I use in a program:
Code:
Public Sub Make_Child_Window(f As Form)
Dim l As Long
l = GetWindowLong(f.hWnd, GWL_STYLE)
l = l Or WS_CHILD
SetWindowLong f.hWnd, GWL_STYLE, l
SetParent f.hWnd, picFrame.hWnd
f.Left = 0
f.Top = 0
f.Width = picFrame.ScaleWidth
f.Height = picFrame.ScaleHeight
End Sub
Where picFrame is the parent-picturebox I use for that.
Check the API textviewer for the declarations.
Oh and I use borderless forms for this.
Hope this helps