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）：
Private Sub Form_Load()
 Dim a As Long
 Dim b As Long
 b = GetSetting("MyApp", "set", "times", 51345)
 a = b Xor 51345
 If a < 30 Then
 MsgBox "现在剩下：" & 30 - a & "试用次数，好好珍惜！"
 a = a + 1
 b = b Xor 51345
 SaveSetting "MyApp", "set", "times", b

 Else
 MsgBox "试用次数已满，请联系gfuuyygy!"
 End If
End Sub

'时间限制的（如10天）
 Private Sub Form_Load()
 Dim a As Long
 a = GetSetting("MyApp", "set", "day", 0)
 If a = 10 Then
 MsgBox "试用期已过，请联系gfuuyygy!"
Else
MsgBox "现在剩下：" & 10 - a & "试用天数，好好珍惜！"
 
 if day(now)-a>0 then
 a = RemainDay + 1
 SaveSetting "MyApp", "set", "times", a
 End if
End if
 End Sub