可用注册表简单地保存已用的天数或次数

'次数限制（如３０次）如下：
Private Sub Form_Load()
Dim RemainDay As Long
RemainDay = GetSetting("MyApp", "set", "times", 0)
If RemainDay = 30 Then
MsgBox "试用次数已满，请……"
Unload Me
End If
MsgBox "现在剩下：" & 30 - RemainDay & "试用次数，好好珍惜！"
RemainDay = RemainDay + 1
SaveSetting "MyApp", "set", "times", RemainDay
End Sub

'时间限制的（如３０天）
Private Sub Form_Load()
Dim RemainDay As Long
RemainDay = GetSetting("MyApp", "set", "day", 0)
If RemainDay = 30 Then
MsgBox "试用期已过，请……"
Unload Me
End If
MsgBox "现在剩下：" & 30 - RemainDay & "试用天数，好好珍惜！"
if day(now)-remainday>0 then RemainDay = RemainDay + 1
SaveSetting "MyApp", "set", "times", RemainDay
End Sub