Minimizeall

Sub mnuWindows_Click(Index as integer)
Select Case Index
Case 1
'minimize

For t% = 1 To Forms.Count - 1
Forms(t%).WindowState = 1
Next t%
Case 2
'restore

For t% = 1 To Forms.Count - 1
Forms(t%).WindowState = 0
Next t%
End Select
End Sub

make a MDIform with several child forms
and a menu on the MDI form with two options:
mnuWindows.caption = "minimize"
index = 1
mnuWindows.caption = "restore"
index = 2
Put the next code on the right place and press F5