This would probably be best:

I posted it as a new thread, because I couldn't find this one, but then when I found this thread again, I adjusted the code so that it is perfect for your needs

VB Code:
  1. 'In the form's code module
  2. Option Explicit
  3. Private Sub Form_Load()
  4.     'Save handle to the form.
  5.     gHW = Me.hwnd
  6.     'Begin subclassing.
  7.    Hook
  8. End Sub
  9. Private Sub Form_Unload(Cancel As Integer)
  10.     'Stop subclassing.
  11. Unhook
  12. End Sub
  13.  
  14. 'In a module
  15. Option Explicit
  16.  
  17.       Private Const GWL_WNDPROC = -4
  18.       Private Const WM_GETMINMAXINFO = &H24
  19.  
  20.       Private Type POINTAPI
  21.           x As Long
  22.           y As Long
  23.       End Type
  24.  
  25.       Private Type MINMAXINFO
  26.           ptReserved As POINTAPI
  27.           ptMaxSize As POINTAPI
  28.           ptMaxPosition As POINTAPI
  29.           ptMinTrackSize As POINTAPI
  30.           ptMaxTrackSize As POINTAPI
  31.       End Type
  32.  
  33.       Global lpPrevWndProc As Long
  34.       Global gHW As Long
  35.  
  36.       Private Declare Function DefWindowProc Lib "user32" Alias _
  37.          "DefWindowProcA" (ByVal hwnd As Long, ByVal wMsg As Long, _
  38.           ByVal wParam As Long, ByVal lParam As Long) As Long
  39.       Private Declare Function CallWindowProc Lib "user32" Alias _
  40.          "CallWindowProcA" (ByVal lpPrevWndFunc As Long, _
  41.           ByVal hwnd As Long, ByVal Msg As Long, _
  42.           ByVal wParam As Long, ByVal lParam As Long) As Long
  43.       Private Declare Function SetWindowLong Lib "user32" Alias _
  44.          "SetWindowLongA" (ByVal hwnd As Long, _
  45.           ByVal nIndex As Long, ByVal dwNewLong As Long) As Long
  46.       Private Declare Sub CopyMemoryToMinMaxInfo Lib "KERNEL32" Alias _
  47.          "RtlMoveMemory" (hpvDest As MINMAXINFO, ByVal hpvSource As Long, _
  48.           ByVal cbCopy As Long)
  49.       Private Declare Sub CopyMemoryFromMinMaxInfo Lib "KERNEL32" Alias _
  50.          "RtlMoveMemory" (ByVal hpvDest As Long, hpvSource As MINMAXINFO, _
  51.           ByVal cbCopy As Long)
  52.  
  53.       Public Sub Hook()
  54.           'Start subclassing.
  55.           lpPrevWndProc = SetWindowLong(gHW, GWL_WNDPROC, _
  56.              AddressOf WindowProc)
  57.       End Sub
  58.  
  59.       Public Sub Unhook()
  60.           Dim temp As Long
  61.  
  62.           'Cease subclassing.
  63.           temp = SetWindowLong(gHW, GWL_WNDPROC, lpPrevWndProc)
  64.       End Sub
  65.  
  66.       Function WindowProc(ByVal hw As Long, ByVal uMsg As Long, _
  67.          ByVal wParam As Long, ByVal lParam As Long) As Long
  68.           Dim MinMax As MINMAXINFO
  69.  
  70.           'Check for request for min/max window sizes.
  71.           If uMsg = WM_GETMINMAXINFO Then
  72.               'necesary for the caption of an MDI child (when maximized)
  73.               '(Thanks to Marvin Chinchilla for this information)
  74.               WindowProc = CallWindowProc(lpPrevWndProc, hw, uMsg, _
  75.         wParam, lParam)
  76.               'Retrieve default MinMax settings
  77.               CopyMemoryToMinMaxInfo MinMax, lParam, Len(MinMax)
  78.  
  79.               'Specify new minimum size for window.
  80.               MinMax.ptMinTrackSize.x = (6000 / Screen.TwipsPerPixelX)
  81.               MinMax.ptMinTrackSize.y = (7365 / Screen.TwipsPerPixelY)
  82.  
  83.               'Specify new maximum size for window.
  84.               MinMax.ptMaxTrackSize.x = Screen.Width
  85.               MinMax.ptMaxTrackSize.y = Screen.Height
  86.  
  87.               'Copy local structure back.
  88.               CopyMemoryFromMinMaxInfo lParam, MinMax, Len(MinMax)
  89.  
  90.               WindowProc = DefWindowProc(hw, uMsg, wParam, lParam)
  91.           Else
  92.               WindowProc = CallWindowProc(lpPrevWndProc, hw, uMsg, _
  93.                  wParam, lParam)
  94.           End If
  95.       End Function

Tell me what you think