Public Declare Function GetWindowPlacement Lib "user32" Alias "GetWindowPlacement" (ByVal hwnd As Long, lpwndpl As WINDOWPLACEMENT) As Long

Public Type POINTAPI
        x As Long
        y As Long
End Type
Public Type RECT
        Left As Long
        Top As Long
        Right As Long
        Bottom As Long
End Type

Public Type WINDOWPLACEMENT
        Length As Long
        flags As Long
        showCmd As Long
        ptMinPosition As POINTAPI
        ptMaxPosition As POINTAPI
        rcNormalPosition As Rect
End Type

Public Const SW_SHOWMINIMIZED =  2 
Public Const SW_SHOWMAXIMIZED =  3 
Public Const SW_SHOWNORMAL =  1 


Dim wp as WINDOWPLACEMENT
Dim ret as Long

'HWND - hWnd окна , которое ищешь

wp.length = Len(wp)
ret=GetWindowPlacement (HWND,wp)

Select Case wp.showCmd
Case SW_SHOWMINIMIZED 
   Debug.print "MINIMIZED"
Case SW_SHOWMAXIMIZED 
   Debug.print "MAXIMIZED"
Case SW_SHOWNORMAL 
   Debug.print "NORMAL"
End Select